Method for forming the image in millimetre and sub-millimetre wave band (variants), system for forming the image in millimetre and sub-millimeter wave band (variants), diffuser light (variants) and transceiver (variants)

ABSTRACT

The invention relates to the field of computer diagnostics. The method consists in the steps of forming radiation forming in this wave range, consisting of separate partial radiations, which are different from each other by values of their physical features, directing of the formed radiations into a side of the observed object, receiving a radiation, dispersed from the observed object, through a focusing element, transforming of the received radiation in electrical signals and forming a synthesized enhance image of the observed object by combining said given electrical signals. Besides, each separate partial radiation is additionally distinctly encoded for example by means of its modulation, which differs from a modulation of other partial radiations, the partial radiations are directed to a diffuser for decreasing their spatial coherence and/or their dispersing by means of different portions of the diffuser in order to create an additional distinctly encoded partial radiations with an additional modulation, corresponding to an angle of impingement onto the observed object. After reflecting of the radiation from the observed object the step of focusing of this radiation to a receiving device is realized, which accomplishes a transforming of set of partial radiations in a corresponding array set of electrical signals, there is realized the step of decoding of partial electrical signals, corresponding to said partial radiations, from each of said electrical signals of said array set there are formed partial images from array sets with various partial electrical signals and then an combination of the partial images or their portions is realized in order to form enhanced resultant image of the object.

FIELD OF THE INVENTION

The present invention relates to real time computer diagnostics, inparticular, to systems and methods for remote detection of weapons,explosives and drugs, concealed on person body beneath its clothes or inluggage, which are based on the quasi-optical imaging of such items, inparticular in the range of millimeter and submillimeter waves.

BACKGROUND OF THE INVENTION

Detection of concealed objects based on formation of their images,millimeter and submillimeter wave (hereinafter referred to as“MMW/SMMW”) radiation has advantages due to high level of itspermeability through the atmosphere under foul weather conditions andthrough various fabrics, plastic, ceramic, wooden materials and othermedia being opaque in the visible range. Owing to a relatively shortwavelength of the MMW/SMMW radiation there are opportunities ofdesigning of imaging systems exhibiting quite high spatial resolution informed images. Such imaging systems may be effectively used forsurveillance goals in various sensitive crowded areas and/or ofincreased significance ones (airports, courts, banks, places ofoccurrence of very important persons and so on) in order to providereal-time remote stealthy detection of concealed weapon, drugs,contraband and explosive including under conditions of promptly varyingsituation.

The known and traditional widely-used methods of disclosing (detecting)weapon and contraband carried by persons through entries and exits ofsecured areas are based on usage of simple metal detector devicessensitive to induction changes in an observed area. Possibilities of themajority of the methods are limited only by binary (yes/no) detection ofthe presence of metallic items, without revealing any details, featuresor even information about item location. Such devices cannot be used forstealthy, efficient and real time contraband detection with a low levelof false alarm. Such conventional detection systems are not effectivebecause they are not sensitive to plastic and ceramic weapons. In orderto reliably visualize and identify this said new class of weapons,explosive, drugs, mines as well as an ordinary weapons, but withenhanced level of safety and with low level of false alarms, novel,methods and correspondent technical systems are required.

The usage of MMW/SMMW imaging systems for any objects, being able toreflect or emit MMW/SMMW radiation allows to solve said problems. Itbecomes possible owing to the fact that the MMW/SMMW radiation arecapable to permeate clothes with negligible attenuation and withoutharmless for human health as opposed to X-ray radiation or microwaveradiation. Reflection and absorption characteristics of human skin forMMW/SMMW radiation are substantially different from the samecharacteristics of ceramic and plastic weapons and narcotics as well asfrom ones of the majority of materials, used for a manufacture of weaponand explosive.

It Is known that passive radiometric MMW/SMMW imaging systems areinherently ineffective indoor, wherein the majority of inspectionprocedures are performed, This ineffectiveness is conditioned by the lowlevel of radiometric brightness temperature contrast in illumination ofthe objects being located indoor in comparison with the items locatedoutdoor, wherein the items are illuminated by means of “cold” sky,brightness temperature of which is about T=70 K, and by means of “warm”surface of the Earth with the brightness temperature near T=300 K.

In outdoor said illumination contrast within the object may be more than200 K, while indoor (in the enclosed rooms) such a contrast is not morethan of from 5 to 7 K in the best case. Since state-of-the-art real timeradiometric imaging systems have a temperature sensitivity of about 1 K,radiometric images generated by such systems exhibit low visible qualitywith high level of noises caused by said low contrast.

A realization of potential capabilities of active MMW/SMMW imagingsystems is possible only under certain conditions, which are mainlyimposed on physical features of the radiation, illuminating the observedobject. Firstly it relates to illumination of observable area withradiation exhibiting a low level of its coherency. This is necessarycondition but not enough one. In any case non-observance of thiscondition results in the fact that the images being formed by MMW/SMMWimaging systems exhibit high level of coherent noises andcorrespondingly low visible quality and informational content.

There is known a system for MMW/SMMW imaging, comprising at least oneillumination composite source of MMW/SMMW radiation consisting of a setof independent component sources of MMW/SMMW radiation, wherein physicalfeatures of radiation of each said component source are distinct withrespect to physical features of radiation of any other said componentsource of the set; focusing means intended for focusing the illuminationradiation, after reflection of one by an observable object and itssurroundings onto receiving means, designed with a function ofindependent reception of radiation portions, incident from complementaryportions of the imaging system field of view in which observable objectis located, and for conversion of said radiation portions into an arrayof correspondent electric signals, wherein output of said receivingmeans is coupled to a processing means intended for forming an image ofthe observable object and its surroundings as well as for mapping thisimage on displaying means, besides, each pixel of the image is formedfrom correspondent electrical signal of said array of said electricalsignals, every of which correspondent a particular radiation portionreflected by a spatially determined portion of the observed object andthe surroundings (see U.S. Pat. No. 5,227,800, Int. CI.: G 01 S 13/89,Date of Publication: Jul. 13, 1993).

The mentioned source of information was taken as a prototype for thedeclared devices.

From this source of information there is also known a method forMMW/SMMW consisting in the steps of: forming MMW/SMMW radiation,consisting of partials, being distinct from one another by radiationphysical features, directing formed radiation toward the object underobservation, receiving via a focusing element the radiation, incidentfrom the area of location of the observable object, converting thereceived radiation into electrical signals and forming a visible imageof the observable object from said electrical signals.

The mentioned source of information was taken as a prototype for thedeclared methods.

Aforesaid prior art method of active imaging and the correspondingMMW/SMMW

imaging system are based on an original method of forming spatiallynon-coherent quasi-monochromatic radiation in the area of inspection.The peculiarity of the method and system of imaging for detection of theobject consists in usage of array of spatially-distributed point-likesources of MMW/SMMW radiation as illumination device. The point sourcesof the array are sources of quasi-monochromatic radiation with asomewhat various carrier frequencies (the carrier frequencies of thesources are differ no more than manufacture tolerances for the sources).The arrays are intended for the object illumination with radiationexhibiting decreased spatial coherency. The image of the object isfocused onto multi-element receiving array (MRA) by means of focusinglens. A set of electrical signals is generated by means of MRA and isfurther processed (frequency down-converted, amplified, rectified,filtered and so on) by means of electronic processing means in such amanner that the image of the object is formed and visualized on thescreen of correspondent display.

An essential drawback of such systems is in the fact that it isnecessary to use arrays with a very large quantity of the point sources.It makes the arrays expensive and they are not suitable for wideapplications. The drawback is associated with the fact that a degree ofspatial coherency in the plane of the object under observationessentially depends on the relationship between a size of array ofspatially distributed non-coherent sources and a distance between saidarray and the object. Owing to this relationship the sizes of the arrayshould be sufficiently large, when distances between the imaged objectsand input pupil of imaging system are standard (which are more than 1 to2 m). Therefore, the best results for imaging may be obtained only forthe arrays, which have large sizes (upon an invariable spatial densityof the point sources), but hence in case of very expensive arrays.

An essential drawback of the system consists in that in the millimeterrange it is impossible to obtain a quality image by means of only simpledestruction of spatial coherence of quasi-monochromatic radiation in thearea of the object location by analogy with optical systems. It takesplace owing almost specular reflection of millimeter wave range fromobjects being interest for remote inspection in contrast to a diffusereflection of radiation in optical range for practically all objects(except for limited quantity of mirror-like objects).

Another drawback of these methods and system consists in that it ispractically impossible to use multi-frequency (wide-band) radiation forillumination of the object. Design of multi-element array of pointsources, in which each such a source will be capable to emit a radiationwith sufficiently wide spectral composition, is not realizable and forthis reason the usage of such system is impossible.

SUMMARY OF THE INVENTION

The present invention is intended for a solution of the mentionedproblems in accordance with which a final (resultant) image in theimaging system is obtained as a result of analysis and further synthesisof sufficient quantity of partial images of the observed object, beingobtained independently with respect to each other, and each of which ischaracterized by independent (and different from each other) set ofradiation physical features. A carrier frequency of illuminationradiation, its polarization state, an angle of incident and so on arerelated to such radiation physical features. The analysis and synthesisof such images (as a “synthesis” it may be understood, for example, as aweighed summation of the partial images and/or their weighted portions)being carried out by means of analogous and digital electronic (opticaland electronic) means or their combinations.

Such a extended set of partial images each of which exhibits varioussets of values of physical features allow to perform enhanceidentification of objects and noise and other disturbances in theresultant image. Having an access to different portions of the partialimages, distinctly containing the object and the disturbance, it ispossible to weighted combined of the portions with according to chosencriteria, for example, to minimize a level of the disturbance of qualityof the resultant combined image and to decrease of its informationalcontents. As a result, unique possibilities are opened with respect toreliable detection of distinctive peculiarities of observed objects andto increasing of their true identification.

The result, obtained in this case, consists in the detection of maskedobjects on a human body or in a luggage of people independently on amaterial, whom which this object is made on the base of its imaging withan improved visual quality and informational contents.

The mentioned technical result for the system is obtained that thesystem for millimeter and sub-millimeter wave imaging, comprising atleast one source of millimeter or sub-millimeter wave radiation carriedout in the form of set of separate independent elements of radiation,values of physical features of radiation of each from which aredifferent with respect to values of physical features of radiation ofother elements of radiation, an element for focusing a radiation,reflected from an object of observation, in the direction of receivingdevice, designed with a function of independent receiving of radiation,impinging from corresponding complementary (mutually adding to whole)portions of the area of location of the observed objects and itstransforming into an array set of corresponding electrical signals,outputs of which are linked with a processor in order to forming theobserved object image and surrounding area of location and for itsmapping on display, besides, each element of the image is formed bymeans of corresponding electrical signal from this array set, to which aspatially determined portion of the observed and of surrounding area ofits location corresponds, is provided with a diffuser, positioned at adistance from a source of radiation for the radiation receiving and itsdissipating in a side of observation area, each separate independentradiation element of the radiation source is designed with a capabilityof the radiation encoding by means of modulation of the last, which isdifferent with respect to a modulation of other separate independentradiation elements, the diffuser is designed with a capability ofrealization of function of decreasing the spatial coherence of impingedradiation and/or with a capability of realization of function of theimpinging radiation dissipating by means of spatially different variousportions of the diffuser with an additional encoding of the radiation bymeans of modulation of dissipating properties of said portions of thediffuser, a receiving means is designed with a capability of independentreceiving of each encoded radiation component, impinging from theobserved object location area, and of transforming each electricalsignal from the array set into a set of electrical signals, besides,each electrical signal of their set corresponds with a separate encodedcomponent of radiation, a processor unit is designed with functions ofindependent receiving of separate electrical signals, transforming ofeach array set of the electrical signals, obtained from electricalsignals with the same encoding, into corresponding to it a correspondingpartial image and transforming a resultant image of the observes objectand area of its location by means of combining of separate partialimages or their portions.

The mentioned result of the first method is obtained by that in a methodfor millimeter and sub-millimeter wave imaging, consisting in the stepsof forming a radiation in the millimeter and sub-millimeter range ofwaves, consisting of separate partial radiations, differing from oneanother by values of radiation physical features, in directing of theformed radiations into a side of the observed object, in a receiving aradiation, dissipated from the observed object, through a focusingelement in transforming of the received radiation in electrical signalsand in forming a visually accepted image of the observed object inaccordance with the given electrical signals, each separate partialradiation is additionally encoded by means of its modulation, whichdiffers from a modulation of other partial radiations, the partialradiations are directed to a diffuser for decreasing their spatialcoherence and/or their dispersing by means of different portions of thediffuser in order to create an additional modulation, corresponding toan angle of impingement onto the observed object, after reflecting ofthe radiation from the observed object a focusing of this radiation andits transferring to a receiving means are realized, the receiving meansfulfils the step of receiving of this radiation independently on eachportion of observed space in the area of the observed object locationand a transferring of set of radiation portions in a corresponding arrayset of electrical signals, the partial electrical signals, correspondingto said partial radiations, are decoded, partial images from each ofsaid electrical signals of said array set from array sets with variouspartial electrical signals are formed and then a combining of thepartial images and/or their portions is realized in order to formenhanced resultant image of the object and then to display one.

The mentioned result of the second method is obtained by that in amethod for millimeter and sub-millimeter wave imaging, consisting in thesteps of forming a radiation in the millimeter and sub-millimeter rangeof waves, consisting of separate partial radiations, differing from oneanother by values of physical features, in directing of the formedradiations into a side of the observed object, in a receiving aradiation, dispersed from the observed object area location, through afocusing element in transforming of the received radiation in electricalsignals and in forming a visually accepted image of the observed objectin accordance with the given electrical signals, each separate partialradiation is additionally encoded, including by means of its modulation,which differs from encoding including modulation of other partialradiations, the partial radiations are directed to the observed object,after reflecting of the radiation from the observed object the step offocusing of this radiation is realized on a receiving means, wherein areceiving of this radiation is fulfilled independently on each portionof observed space and wherein the step of converting of set ofradiations, impinging from each complementary portion of observed spaceinto the corresponding array set of electrical signals is realized, thepartial electrical signals, corresponding to said partial radiations,are decoded, partial images from array sets of partial electricalsignals are formed from each said electrical signal of said array setand then a combining of the partial images and/or their portions (sizesof which may be small even up to a single pixel of such images) isrealized in accordance with a selected algorithm of processing of saidsignals in order to form visually accepted resultant image of theobject.

The obtainment of the result is based on that in a system ofillumination of MMW/SMMW imaging system there is used only one ordetermined quantity of MMW/SMMW source (oscillators), each of generatedpartial components of radiation may be characterized by means of variousvalues of carrier frequencies and polarization and which may be encoded(for example modulated) by different way. Resulting composite radiationmay be directed to an observed object within the inspection area or itmay be primarily directed to a spatially distributed diffuser. Thisdiffuser may be in the form of a spatially distributed diffusivedisperser, which is not capable to destruct a spatial coherence ofradiation, impinging on it, or in the form of spatially distributeddiffuser with an electronic control, which is capable to destruct thespatial coherence of the radiation. In the last case the diffuser may beprovided with a function of creation of additional partial components ofradiations by means of distinctive dissipation of impinging radiation bymeans of various spatial portions of the diffuser and by means ofadditional encoding novel partial component by a distinctive modulationof dispersing properties of said various spatial portions of thediffuser. The distinctive encoding of the various partial componentallows to receive them and to process them by means of receiving meansof the imaging system independently on each other.

Various partial images, formed from corresponding partial components ofradiation, may be optimally processed in imaging system analogous and/ordigital init for processing images in order to obtain a necessaryresult, concerning to an obtainment of necessary information from themand improvement a visual quality.

By means of combining of various partial images upon the usage of thesame data volume it is appears a possibility of realizing of digitalsynthesis of images, which are characterized by means of variousconditions of illumination, including an illumination with varied degreeof both the temporary and spatial coherence, of varied polarization, ofan angle of the object backlighting and so on upon the presence ofcapability of automatic elimination of radiation components, destructinga quality of such synthesized images.

The mentioned features are essential ones for each of the inventionobjects and they are interconnected between each other with a formationof stable combination of the features for each of the objects.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by means of concrete examples,which, however, are not uniquely possible ones, but they visuallydemonstrate a capability of obtainment of the necessary result by meansof adduced combinations of the essential features.

FIG. 1 shows generalized block diagram of an active MMW/SMMW imagingsystem;

FIG. 2 is a schematic representation of procedure of forming the firstpartial image of an object;

FIG. 3 is a schematic representation of procedure of forming the secondpartial image of an object;

FIG. 4 is a schematic representation of procedure of forming the thirdpartial image of an object;

FIG. 5 is a final (resultant) image of an object, synthesized bysummation of the partial images, shown in FIG. 2-4;

FIG. 6 is a synthesized image, obtained by summing two partial images,exhibiting almost the same values of their radiation of physicalfeatures.;

FIG. 7 is a synthesized image, obtained by summing two partial images,which values of physical features differ from each other distinctly;

FIG. 8 is a summed image, in a case of summing partial images one ofwhich is resulted from specular reflection of object-illuminatingradiation.

FIG. 9 is a multiplicative image of an object.

FIG. 10 is a block block representation of multi-frequency system offorming images in the range of millimeter and sub-millimeter waves;

FIG. 11 is a one-frequency image;

FIG. 12 is a five-frequent synthesized (summarized) image;

FIG. 13 shows a scale of gradations for a level of pixel value signal inthe images, shown in FIG. 11 and FIG. 12;

FIG. 14 represents a waveguide realization of MMW/SMMW multi-frequencypoint-like source with controlled spectral density of illuminatingradiation;

FIG. 15 shows a cross-section of antenna-loaded impedance forantenna-array diffuser upon the first example of embodiment;

FIG. 16 is the same section, shown in FIG. 15 upon a frontal position;

FIG. 17 shows an indicatrix of radiation scattering, shown in FIG. 15,when an impedance of load is matched to antenna input impedance;

FIG. 18 is the same indicatrix, shown in FIG. 17, but in case when theimpedance of load is not matched to the antenna input impedance;

FIG. 19 is an example of diffuser designed as a spatially distributedset of independent quasi-optical switches of radiation;

FIG. 20 is a wide-band independent quasi-optical switch of radiation,functioning as a switched polarization grid;

FIG. 21 is a frequency selective independent quasi-optical switch ofradiation, which is capable to realize frequency selection of impingingradiation;

FIG. 22 shows interconnections in the independent quasi-optical switchof radiation;

FIG. 23 is a layout of conducting elements and diodes beingquasi-optically biased;

FIG. 24 is a schematic layout of quasi-optical switch demonstratingcoupling between elemts;

FIG. 25 shows an array of radiation-encoding diffuser, consisting ofspatially inserted in each other and adding sub-arrays, in each of whichcorresponding independent quasi-optical switches of radiation areoriented by the same manner in one direction for one sub-array and inanother direction for another sub-array;

FIG. 26 shows a principle of amplitude modulation of spatial coherenceradiation by means of independent quasi-optical switches of radiation;

FIG. 27 represents a principle of phase modulation of wave front bymeans of array of independent quasi-optical switches of radiation, eachof which modulates independently a phase of reflected radiation;

FIG. 28 is a phase antenna array of passing type;

FIG. 29 is a phase antenna array of reflecting type;

FIG. 30 shows a spatially distributed surface of diffuser, distictspatial portion of which are illuminated by various radiation beams;

FIG. 31 is the first example of simple diffuser;

FIG. 32 is the second example of diffuser;

FIG. 33 represents a possible construction of diffuser, consisting ofset of relatively-small random-surface diffusers, each of which rotatesaround itself axis;

FIG. 34 represents a block diagram of active imaging system based onusage of radiation-encoding diffuser, consisting of the constituentrandom-surface diffusers each of which is capable only to destruct thespatial coherence of scattered radiation;

FIG. 35 represents a schematic view of an active MMW/SMMW imaging systemfor detection of threat objects concealed on human body based on anillumination of inspection area by multi-parametric radiation beingprimarily decomposed into multiple partial radiation components byradiation-encoding diffuser;

FIG. 36 represents possible phasor diagrams of object-illuminatingradiation in a spatial point near object surface and their possibletransformation as a result of their processing;

FIG. 37 represents a schematic view of active imaging system showingmechanism of forming a specular and diffuse reflections ofobject-illuminating radiation;

FIG. 38 shows cross-section view of a part of radiation-reflectingobject surface.;

FIG. 39 shows cell structure of a diffuser intended for scatteringmultiple partial radiation components each of which is distinctlyencoded by correspondent diffuser cell;

FIG. 40 shows a fine sideband spectrum of diffuser-scattered partialradiation components being distinctly encoded by their frequencymultiplexing and which propagates in a observation area before theirinteraction with observable objects

FIG. 41 shows a fine sideband spectrum of the object-scattered radiationreceived by a receiving element of receiving array of imaging system;

FIG. 42 is the same fine sideband spectrum of the object-scatteredradiation as shown in FIG. 41 after its processing for decreasingspecular spectrum components;

FIG. 43 is a graphical representation of peculiarities of distributionof spectral lines of encoded signals, corresponding to the thinstructure of FIG. 41 spectrum in the form of two-dimensionalarray-diagram;

FIG. 44 is a graphical representation of peculiarities of distributionof spectral lines of radiation signals encoded by frequencymultiplexing, corresponding to the fine structure of FIG. 43 spectrum inthe form of two-dimensional matrix-diagram;

FIG. 45 is an illustration, demonstrating a complete set ofmulti-parameter image information, obtained by a receiving element ofreceiving array, in the form of set of independent matrix-diagrams eachof which exhibits distinct values of the physical features of radiationilluminating the diffuser;

FIG. 46 is an illustration of peculiarities of forming of radiometricand a resultant image combined from set of the seven partial images;

FIG. 47 is an schematic view of threat object concealed beneath clotheswith an indication of possible radiation reflections generating variouspartial images;

FIG. 48 is an schematic illustration of procedure of formation ofresultant (syuthesized) images from sets of partial images with andwithout extraction of noise partial images;

FIG. 49 demonstrates results of conventional digital processing ofradiometric-like and resultant (synthesized) images;

FIG. 50 represents variants of various combining of diffuser cells intoclusters;

FIG. 51 is a block diagram of OMCS generator, consisting of pairedPLL-linked oscillators with a stabilized frequency of their frequencydifference beat signal;

FIG. 52 is a block diagram of the first example OMCS generator producingmultiple phase-locked oscillators;

FIG. 53 is a block diagram of the second example OMCS generatorproducing multiple phase-locked oscillators;

FIG. 54 is a block diagram of first example OMCS generator producingmultiple phase-locked oscillators;

FIG. 55 represents an input part of super-heterodyne receiving channelof imaging system receiving device, the first block diagram of inputunit of receiving means;

FIG. 56 is the second block diagram of input unit of receiving means;

FIG. 57 is third block diagram of input unit of receiving means;

FIG. 58 is fourth block diagram of input unit of receiving means;

FIG. 59 is fifth block diagram of input unit of receiving means;

FIG. 60 is an example of a communication transceiver;

FIG. 61 shows a spectrum of a frequency difference beat signal spectrum;

FIG. 62 represents a characteristic distribution of frequency differencebeat signal spectrum for demonstrative a case of possible high spectraldensity of frequency multiplexed radiation components,;

FIG. 63 shows a spectrum of frequency difference beat signal at output asquare-law detector in receiving channel based on usage directamplification and detection input circuits;

FIG. 64 shows three pairs of diffuser cells, which allow to formdifferent images;

FIG. 65 is a block-diagram of imaging system for forming volume images,based on the usage of Fresnel's lens and multi-frequency diffuser-basedillumination system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In accordance with the present invention the first method for millimeterand sub-millimeter wave imaging, consists in the steps of forming acomposite radiation in the millimeter and sub-millimeter range of waves,consisting of separate partial radiations, differing from one another byvalues of their physical features, directing the formed radiationsforward to the observed object, receiving the? radiation, beingscattered with the observed object, from a radiation-focusing element,transforming the received radiation in electrical signals and in forminga visually accepted image of the observed object in accordance with thegiven electrical signals. In accordance with this method, each separatepartial radiation is additionally encoded by means of its modulation,which differs from a modulation of other partial radiations, the partialradiations are directed to a diffuser for decreasing their spatialcoherence and/or their dispersing by means of different portions of thediffuser in order to create an additional modulation, corresponding toan angle of impingement onto the observed object, after reflecting ofthe radiation from the observed object the steps of focusing of thisradiation and its transferring to a receiving means are realized, thereceiving means fulfils a receiving of this radiation independently oneach portion of observed space in the area of the observed objectlocation and a transferring of set of radiations in a correspondingarray set of electrical signals, the partial electrical signals,corresponding to said partial radiations, are decoded, partial imagesfrom each of said electrical signals of said array set from array setswith various partial electrical signals are formed and then a combiningof the partial images and/or their portions is realized in order to forma resultant image of the object and to display one.

The method for millimeter and sub-millimeter wave imaging in accordancewith the second its embodiment consists in the steps of forming aradiation in the millimeter and/or sub-millimeter range of waves,consisting of separate partial radiations, differing from one another byvalues of their physical features, directing of the formed radiationsinto a side of the observed object, receiving a radiation, dissipatedfrom the observed object location area (inspection area), through afocusing element, in transforming of the received radiation inelectrical signals and forming a visually accepted image of the observedobject in accordance with the given electrical signals. In accordancewith this method, each separate partial radiation is additionallyencoded, for example by means of its modulation, which differs from amodulation of other partial radiations, the partial radiations aredirected to the observed object, after reflecting of the radiation fromthe observed object the step of focusing of this radiation is realizedon a receiving means, wherein a receiving of this radiation is fulfilledindependently on each portion of observed space and wherein atransferring of set of radiations, impinging from each complementaryportion of observed space into the corresponding array set of electricalsignals is realized, the partial electrical signals, corresponding tosaid partial radiations, are decoded, partial images from array sets ofpartial electrical signals are formed from each said electrical signalof said array set and then a combining of the partial images and theirportions (sizes of the portions may be very small even up to a singlepixel of such images) is realized in accordance with a selectedalgorithm of processing of said signals in order to form a resultantimage of the object and further display one.

The system for millimeter and sub-millimeter wave imaging comprises atleast one source of millimeter or sub-millimeter wave radiation carriedout in the form of set of separate independent elements of radiation,all or a part of values of their radiation physical features of eachfrom which are different with respect to values of correspondentphysical features of radiation of other elements of radiation, anelement for focusing radiation, which is dissipated within theinspection are by the observed object, on a receiving device, which isdesigned with a function of independent receiving of radiation,dissipated by various spatial portions of the observed object and/or itslocation area, positioned in the field of view of said focusing element,and transforming it in a corresponding array set of correspondingelectrical signals, outputs of the receiving device are linked with aprocessor in order to transforming said array set of electrical signalsinto a corresponding matrix image of the observed object and/or itslocation area and this image mapping on display, besides, each elementof the image is formed by means of corresponding electrical signal,which was obtained in consequence of transforming by the receivingdevice that radiation, which is dispersed by means of correspondingspatially determined portion of the observed object and/or surroundingarea of its location and is correspondingly focused on the receivingdevice by means of said focusing element. The system is provided with adiffuser, positioned at a distance from a source of radiation andintended for its illumination by means of radiation of said source ofradiation and sequential dissipation of this radiation in the directionof the observed object location area, independent radiation elements aredesigned with fixed or varied in time and by value said distinctivephysical features, the diffuser is designed with a capability ofrealization of function of decreasing the spatial coherence of impingedradiation and/or with a capability of realization of function of theimpinging radiation diffuser dissipating by means of spatially differentvarious portions of the diffuser with an additional encoding of thedissipated radiation by means of different modulation of dissipatingproperties of said portions of the diffuser and with a realization offunction of decreasing of spatial coherence of radiation, dispersed bythe diffuser, a receiving device is designed with a capability ofindependent receiving of each encoded radiation component in all theranges of variations of values of radiation physical features, impingingfrom the observed object location area, and of transforming eachelectrical signal from said array set of electrical signals by means ofdecoding into an additional set of electrical signals, each of whichcorresponds with a distinctly encoded component of radiation, each ofwhich is focused on the receiving device from a corresponding spatialportion of the object or its location area, and each of which isdistinctly received and decoded in one or in different moments of timeduring the receiving by the receiving device the radiations, reflectedall said spatial portions of the observed object and/or observation areaand during a time of variations of values of said physical features ofradiation in all said their sufficiently different values, a processorunit is designed with functions of independent receiving of separateelectrical signals, transforming of each array set of the electricalsignals, obtained from electrical signals with the same encoding, andfor the same values of physical parameters of radiations of a source ofradiation into corresponding to it a partial array image and forming aresultant image of the observes object and area of its location by meansof combining of separate partial matrix images and/or their portions.

In the present system the processor may be designed with a functions ofcontrol of radiation-encoding diffuser elements and with a variation ofvalue distribution of the encoding diffuser with respect to saidportions of the diffuser and with respect to the given algorithm.

In accordance with another example of embodiment the system formillimeter and sub-millimeter wave imaging comprises at least one sourceof millimeter or sub-millimeter wave radiation carried out in the formof set of separate independent elements of radiation, all or a part ofvalues of physical features of radiation of each from which aredifferent with respect to values of correspondent physical features ofradiation of other elements of radiation device, which is designed witha function of independent receiving of radiation, dissipated by variousspatial portions of the observed object and/or its location area,positioned in the field of view of said focusing element, andtransforming it in a corresponding array set of corresponding electricalsignals, outputs of which are connected to a processor in order totransform said array set of electrical signals into a correspondingmatrix image of the observed object and/or its location area and thisimage mapping on display, besides, each element of the image is formedby means of corresponding electrical signal, which was obtained inconsequence of transforming by the receiving device that radiation,which is dispersed by means of corresponding spatially determinedportion of the observed object and/or surrounding area of its locationand is correspondingly focused on the receiving device by means of saidfocusing element. In this example the system is provided with adiffuser, positioned at a distance from a source of radiation andintended for its illumination by means of radiation of said source ofradiation and sequential dispersing of this radiation in the directionof the observed object location area, independent radiation elements aredesigned with fixed or varied in time and by value said distinctivephysical features, each separate independent radiation element ofradiation source is designed with a capability of encoding itselfradiation, including and its modulation, differing from an encoding ofradiation of other separate independent elements of radiation, thediffuser is designed with a capability of realization of function of theimpinging radiation diffuser dispersing or with a capability ofrealization of function of the impinging radiation diffuser dispersingby means of spatially different various portions of the diffuser with anadditional encoding of the dispersed radiation by means of differentmodulation of dispersing properties of said portions of the diffuserand/or with a realization of function of decreasing of spatial coherenceof radiation, dispersed by it, a receiving device is designed with acapability of independent receiving of each encoded radiation componentin all the ranges of variations of values of radiation physicalfeatures, impinging from the observed object location area, and oftransforming each electrical signal from said array set of electricalsignals by means of decoding into an additional set of electricalsignals, besides, each electrical signal from the additional set of theelectrical signals corresponds to distinctly encoded component ofradiation, each of which is focused on the receiving device fromcorresponding spatial portion of the object or its location area, andeach of which is distinctly received and decoded in one or in variousmoments of time during the receiving by the receiving device theradiations, reflected all said spatial portions of the observed objectand/or observation area and during time of variations of values of saidphysical features of radiation in all said their sufficiently differentvalues, a processor unit is designed with functions of independentreceiving of separate electrical signals, transforming of each array setof the electrical signals, obtained from electrical signals with thesame encoding, and for the same or near the same values of physicalfeatures of radiations of said independent elements of radiations intocorresponding to it a partial array image, and forming a resultant imageof the observed object and area of its location by means of combining ofseparate partial matrix images and/or their portions.

In this system distinctive fixed and/or scanned in value physicalfeatures of radiations of said independent elements of radiations may bespatial directions of propagation of beams of these radiations such thatthe spatially distinctive portions of said diffuser, illuminated bythese radiations, corresponds to various distinctive directions ofcorresponding radiations.

The diffuser for this system may be additionally provided with means forpolarization, isolating from a radiation, reflected by the diffuser, aradiation, which is preferably linearly polarized in the first spatialdirection, but a receiving device is provided with polarization meansfor isolating a radiation, which is received by it and which is linearlypolarized in the second spatial direction. Besides, the first saiddirection may coincide with the second said direction or the first saiddirection may be orthogonal with respect to the second direction.

The system for millimeter and sub-millimeter wave imaging in accordancewith the third example of embodiment comprises one source of millimeteror sub-millimeter wave radiation, an element for focusing a radiation,dissipated by the observed object, on a receiving device, which isdesigned with a function of independent receiving of radiation,dissipated by various spatial portions of the observed object and/or itslocation area, positioned in the field of view of said focusing element,and transforming it in a corresponding array set of correspondingelectrical signals, outputs of which are connected to a processor inorder to transform said array set of electrical signals into acorresponding matrix image of the observed object and/or its locationarea and this image mapping on display, besides, each element of theimage is formed by means of corresponding electrical signal, which wasobtained in consequence of transforming by the receiving device thatradiation, which is dispersed by means of corresponding spatiallydetermined portion of the observed object and/or surrounding area of itslocation/ and is correspondingly focused on the receiving device bymeans of said focusing element. The system, designed in accordance withthis example, is provided with a diffuser, positioned at a distance froma source of radiation and intended for its illumination by means ofradiation of said source of radiation and sequential dissipation of thisradiation in the direction of the observed object location area, theradiation source is designed with fixed or varied in time and by valuephysical feature of its radiation, the diffuser is designed with acapability of realization of function of the impinging radiationdiffuser dissipating or with a capability of realization of function ofthe impinging radiation diffuser dispersing by means of spatiallydifferent various portions of the diffuser with an additional encodingof the dispersed radiation by means of different modulation ofdispersing properties of said portions of the diffuser and with arealization of function of decreasing of spatial coherence of radiation,dispersed by it, a receiving device is designed with a capability ofindependent receiving of each encoded radiation component in all theranges of variations of values of radiation physical features, impingingfrom the observed object location area, and of transforming eachelectrical signal from said array set of electrical signals by means ofdecoding into an additional set of electrical signals, each of whichcorresponds to distinctly encoded component of radiation, each of whichis focused on the receiving device received from corresponding spatialportion of the object or its location area, and each of which isdistinctly and decoded in one or in various instants of time during thereceiving by the receiving device the radiations, reflected all saidspatial portions of the observed object and/or observation area andduring time of variations in value of said physical features ofradiation in all said their sufficiently different values, a processorunit is designed with functions of independent receiving of separateelectrical signals, transforming of each array set of the electricalsignals, obtained from electrical signals with the same encoding, andfor the same values of physical features of radiations of the radiationsource into corresponding to it a partial array image, and forming aresultant image of the observed object and area of its location by meansof combining of separate partial matrix images and/or their portions.

In the this system the processor may be designed with a functions ofcontrol of encoding diffuser elements and with a variation of valuedistribution of the encoding diffuser with respect to said portions ofthe diffuser and with respect to an algorithm, given by the processor.

In accordance with the following example of embodiment the system formillimeter and sub-millimeter wave imaging comprises at least one sourceof millimeter or sub-millimeter wave radiation, an element for focusinga radiation, dispersed by the observed object, on a receiving device,which is designed with a function of independent receiving of radiation,dispersed by various spatial portions of the observed object and/or itslocation area, positioned in the field of view of said focusing element,and transforming it in a corresponding array set of correspondingelectrical signals, outputs of which are linked with a processor inorder to transform said array set of electrical signals into acorresponding matrix image of the observed object and/or its locationarea and this image mapping on display, besides, each element of theimage is formed of corresponding electrical signal, which was obtainedin consequence of transforming by the receiving device that radiation,which is dissipated by means of corresponding spatially determinedportion of the observed object and/or surrounding area of its locationand is correspondingly focused on the receiving device by means of saidfocusing element. The system is provided with a diffuser, positioned ata distance from a source of radiation and intended for its illuminationby means of radiation of said source of radiation and sequentialdispersing of this radiation in the direction of the observed objectlocation area, the radiation source is designed with varied in time andby value at least one physical feature of its radiation, the diffuser isdesigned with a capability of realization of function of the decreasingof spatial coherence of the radiation, dispersed by it, a receivingdevice is designed with a capability of independent receiving of eachencoded radiation component in all the ranges of variations in value ofradiation physical features, impinging from the observed object locationarea, and of transforming each electrical signal from said array set ofelectrical signals by means of decoding into an additional set ofelectrical signals, each of which corresponds to the same or closely thesame values of physical features of radiation of the radiation source,each of which is focused on the receiving device from a correspondingspatial portion of the object or its location area, and each of which isdistinctly received and decoded in one or in various moments of timeduring the receiving by the receiving device the radiations, reflectedall said spatial portions of the observed object and/or observation areaand during time of value variations of said physical features ofradiation in all said their sufficiently different values, a processorunit is designed with functions of independent receiving of separateelectrical signals, transforming of each array set of the electricalsignals, obtained from electrical signals with the same or with closelythe same values of physical features of radiations of the radiationsource into corresponding to it a partial array image, and forming aresultant image of the observed object and area of its location by meansof combining of separate partial matrix images and/or their portions.

For the system, described in this example, the varied physical featureof the radiation source is a directivity of radiations, a variation ofwhich in time results in a sequential in time illumination of variousspatial areas of said diffuser, or the varied physical feature of theradiation source is a the radiation frequency.

In accordance with a further embodiment of the invention the system formillimeter and sub-millimeter wave imaging comprises at least one sourceof millimeter or sub-millimeter wave radiation, carried out in the formof set of separate independent elements of radiation, all or a part ofvalues of physical features of radiation of each from which aredifferent with respect to values of physical features of radiation ofother elements of radiation device, an element for focusing a radiation,dispersed by the observed object, on a receiving device, which isdesigned with a function of independent receiving of radiation,dispersed by various spatial portions of the observed object and/or itslocation area, positioned in the field of view of said focusing element,and transforming it in a corresponding array set of correspondingelectrical signals, outputs of which are connected to a processor inorder to transform said array set of electrical signals into acorresponding matrix image of the observed object and/or its locationarea and this image mapping on display, besides, each element of theimage is formed of corresponding electrical signal, which was obtainedin consequence of transforming by the receiving device that radiation,which is dissipated by means of corresponding spatially determinedportion of the observed object and/or surrounding area of its location,and is correspondingly focused on the receiving device by means of saidfocusing element. The system is provided with a diffuser, positioned ata distance from a source of radiation and intended for its illuminationby means of radiation of said source of radiation and sequentialdispersing of this radiation in the direction of the observed objectlocation area, said element for radiation focusing is designed afrequency-dependent, for which a focal length of this lens depends on afrequency of focused radiation, said set consists of independentelements of the radiation, which are with a fixed sufficientlydistinctive central frequencies of the radiation and/or at least of oneradiation source with a frequency, varied in the sufficiently wide rangeof frequencies, each separate element of radiation of the radiationsource is designed with a capability to encode itself radiation,including also its modulation, and different from radiation encoding ofother separate independent radiation elements, the diffuser is designedwith a capability of realization of diffusive dispersing of impingingradiation by spatially various portions of the diffuser by means ofadditional different encoding of dispersed radiation by means ofdifferent modulation of dispersing properties of said diffuser portionsand/or with a realization of function of decreasing a spatial coherenceof the radiation, dispersed by it, a receiving device is designed with afunction of independent receiving of each encoded component of radiationin all the ranges of variations of physical features of radiation,impinging from the observed object location, and transforming eachsignal from said array set of electrical signals by means of decodinginto an additional set of electrical signals, besides, each ofelectrical signal of the additional set of the electrical signalscorresponds to distinctively encoded component of the radiation, each ofwhich is focused on the receiving device from a corresponding spatialportion of the object or its location area, and each of which isdistinctly received and decoded in one or in various moments of timeduring the receiving by the receiving device the radiations, reflectedall said spatial portions of the observed object and/or observation areaand during time of variations of said physical features of radiation inall said their sufficiently different values, a processor unit isdesigned with functions of independent receiving of separate electricalsignals, transforming of each array set of the electrical signals,obtained from electrical signals with the same encoding and with thesame or with near the same values of physical features of radiations ofsaid independent elements of radiations into corresponding to it apartial array image, and forming a set of resultant images of theobserved object and area of its location by means of combining ofseparate partial matrix images with the same or with near the samevalues of frequency of said radiation source or their portions andforming a three-dimensional image from said set of said resultantimages.

In this system the frequency-dependent element of focusing is a zoneFresnel's lens, but the set of independent elements of radiation mayinclude at least two radiation sources with a frequency varied in widelimits, and each of which is intended for an illumination of spatiallydifferent portions of said diffusers.

Concrete realizations of methods and systems are below considered.

In accordance with the present invention the system for millimeter andsub-millimeter wave imaging comprises at least one source of millimeteror sub-millimeter wave radiation, carried out in the form of set ofseparate independent elements of radiation, physical features ofradiation of each from which are different with respect to physicalfeatures of radiation of other elements of radiation, besides the setmay contain elements of radiation with their radiation physicalfeatures, which are controllably varied.

The system also has an element for focusing a radiation, dispersed bythe observed object, in area of a receiving device, which is designedwith a function of independent receiving of radiation impinging fromcorresponding complementary portions of the observed object locationarea, and for its transformation into an array set of correspondingelectrical signals, besides, a quantity of elements of said array setcorresponds to a quantity of said complementary portions of observedarea; outputs of the receiving device are linked with a processor forforming an image of the observed object and zone of its location and formapping of this image on a display.

Each array element of image is formed by means of correspondingelectrical signal from said array set, and a certain portion of theobject of observation and its location surrounding area corresponds toeach such an element of the image. The system is provided with adiffuser, positioned at a distance from the radiation source forreceiving of its radiation and for its dissipation to a side of the areaof observation.

Each separate independent element-source of radiation of said radiationis carried out with a capability to encode the radiation by means of thelast modulation, which is differs from a modulation of other separateindependent element-sources of radiation. The diffuser is designed witha capability realization a function of diffusive dispersing of impingingradiation or with a capability to realize a function of the impingingradiation diffusive dissipating by means of spatially different variousportions of the diffuser with an additional encoding of the dissipatedradiation by means of different modulation of dissipating properties ofsaid portions of the diffuser and/or with a realization of function ofdecreasing of spatial coherence of impinging radiation. A receivingdevice is designed with a capability of independent receiving of eachencoded radiation component, impinging from the observed object locationarea, and of transforming each electrical signal from said array set ofelectrical signals into an additional set of electrical signals,besides, each electrical signal of the additional set of the electricalsignals corresponds with a distinctly encoded component of theradiation. A processor unit is designed with functions of independentreceiving of separate electrical signals, of transforming of each arrayset of the electrical signals, obtained from electrical signals with thesame encoding into corresponding to it a partial array image and offorming a resultant image of the observed object and area of itslocation by means of combining of separate partial matrix images and/ortheir portions.

In accordance with the present invention the first method for millimeterand sub-millimeter wave imaging, consists in the steps of forming aradiation in the millimeter and sub-millimeter range of waves,consisting of separate partial radiations, differing from one another byphysical features, directing of the formed radiations into a side of theobserved object, receiving a radiation, dissipated from the observedobject, through a focusing element, transforming of the receivedradiation into electrical signals and forming a visually accepted imageof the observed object in accordance with the given electrical signals.

Besides, each separate partial radiation is additionally encoded bymeans of its modulation, which differs from a modulation of otherpartial radiations, the partial radiations are directed to a diffuserfor decreasing their spatial coherence and/or their dispersing by meansof different portions of the diffuser in order to create an additionalpartial radiations with an additional modulation, corresponding to anangle of impingement onto the observed object.

After reflecting of the radiation from the observed object a focusing ofthis radiation and its transferring to a receiving means are realized.

The receiving device fulfils the steps of receiving of this radiationindependently on each portion of observed space in the area of theobserved object location and transferring of set of radiations in acorresponding array set of electrical signals, it realizes a decoding ofthe partial electrical signals, corresponding to said partialradiations, partial images from each of said electrical signals of saidarray set from array sets with various partial electrical signals areformed by the receiving device and then a combining of the partialimages and/or their portions is realized in order to form resultantimage of the object.

The second variant of the method for millimeter and sub-millimeter waveimaging consists in the steps of forming a radiation in the millimeterand sub-millimeter range of waves, consisting of separate partialradiations, differing from one another by physical features, directingof the formed radiations into a side of the observed object, receiving aradiation, dissipated from the observed object area location, through afocusing element in transforming of the received radiation in electricalsignals and i forming a visually accepted image of the observed objectin accordance with the given electrical signals.

Besides, each separate partial radiation is additionally encoded forexample by means of its modulation, which differs from a modulation ofother partial radiations, the partial radiations are directed to theobserved object, after reflecting of the radiation from the observedobject a focusing of this radiation is realized on a receiving means,wherein a receiving of this radiation is fulfilled independently on eachportion of observed space and wherein a transferring of set ofradiations, impinging from each complementary portion of observed spaceinto the corresponding array set of electrical signals is realized, thepartial electrical signals, corresponding to said partial radiations,are decoded, partial images from array sets of partial electricalsignals are formed from each said electrical signal of said array setand then a combining of the partial images and/or their portions isrealized in order to form enhanced resultant image of the observedobject.

Examples of concrete embodiment of the system for millimeter andsub-millimeter wave imaging are below adduced.

The imaging system 1 (see FIG. 1) includes a point-like source (as anindependent radiation element) 2 of radiation in the range of millimeterand sub-millimeter waves. In general case spectral components of theradiation of the source 2 may be possessed by any region of theelectromagnetic spectral range (including infra-red and visibleradiation). In the framework of the present invention a term “MMW/SMMWradiation” will be used for a reference to any region in the range ofmillimeter and sub-millimeter waves, having, for example, spectralcomponents, which are in the range between 30 and 3000 gigahertz (orwavelengths ranging from 0.1 to 10 mm). It is possible a realization, inaccordance with which the source 2 transmits (quasi-monochromatic)radiation exhibiting narrow bandwidth of its spectrum. Such a radiationmay be generated by any conventional fully monolithic source orwaveguide performance source, industrially produced for operating, forexample, at some fixed frequency. The radiation of such a source may bespatially coherent.

A multi-frequency imaging approach, when for illumination of an objectit is used a radiation, consisting of spectral components withessentially distinctive central (carrier) frequencies, is able toprovide lots of advantages. For example, special object-covering filmsmay be developed for goals of concealing of contraband objects. Suchfilms may exhibit radiation scattering characteristics being similar toradiation scattering characteristics of human skin in some particularspectral band. However this is impossible to make the object to beinvisible by usage of such films if a wide-band radiation is used. To beundetected by such an imaging system which operates in wide-bandspectral range is impossible because said scattering properties of humanskin depend on moisture and temperature of surroundings, state ofnervous system of an individual carrying the concealed object (dependingof level of exciting of the individual).

In a preferential embodiment the source 2 should be a radiation sourcetransmitting a wide-band spectrum radiation. In this case the source(oscillator) 2 may consist of one or more (partial) sources(oscillators) 3, 4, 5, each of which generates a radiation(characterized by different physical properties) belonging to differentspectral ranges.

It is preferably that an average intensity of spectral components,generated by partial constituent sources and, may be, their spectrallocation and spectral composition would be individually controlled bycorrespondent controlling means. Outputs (output antennas) of suchpartial constituent MMW/SMMW sources may be physically united into asingle output in such a manner that all said spectral components will beoriginated from practically the same spatial point being a phase centreof the correspondent output antenna (or at least from the same, forexample, horn antenna in case of a waveguide realization of such asource) or from spatially closely-located points. In another embodimentof the invention the source 2 may consist of one or several partialconstituent sources, a radiation of every of which exhibits own specificpolarization states. Said polarization states may be both the same forall said radiation sources and distinctive for different ones.

Controlling systems of such partial constituent sources should becapable to control both the average energy, emitted by said source 2,and spectral localization (but sometimes the spectral composition aswell) of its spectral radiation components. In another preferableembodiment these controlling systems also should distinctly encode theradiation generated by every said partial constituent sources(exhibiting own particular frequency composition and polarizationstate). This will allow to distinctly decode and extracted from compoundradiation received by receiving apparatus of imaging system (byreceiving array and correspondent receiving electronic means).

In accordance with another embodiment of the invention the spectralcomposition of wide-range radiation consists of only a set ofnarrow-band spectral components, the intensity and central frequency ofevery of which may be varied independently. In another embodiment of theinvention only radiation central frequencies may be varied for part ofconstituent sources 3, 4, 5 of the radiation source 2 or for all of themfor goal of a formation of frequency-distinctive partial constituentimages.

A multi-frequency radiation may be directed toward an observed object.In this case there exists possibility to synthesize resultant image ofenhanced quality due to a formation of a set of partial constituentimages exhibiting spatial distributions of spatial coherent specklenoises which are different for different said images. Such synthesizedimage may be obtained by simple summation of said constituent imagesand/or their portions. The radiation may be primarily directed towards asimplified diffuser which is not capable to destroy a spatial coherenceof the radiation but only diffusely scatter the radiation for decreasingits primary high directivity. Such a diffuser may be, for example, asimple brick wall having a surface randomly scattering a radiation. Foroptimal summation of frequency-distinct partial constituent images it isneeded to take into account possible differences in scattering theradiation components with the diffuser and different spectralsensitivity of receiving apparatus. It may be realized both by optimalturning of intensity level of correspondent radiation components and bya posteriori digital processing (for example by increasing a contrast ofcorrespondent partial constituent images). Said summation of wholepartial constituent images or only some portions of them may beperformed, as well, in analogous electronic units of receiving apparatuswhich may be provided with filtration unit or any other unit whichperforms summation of signals of the partial constituent images (or moreprecisely, summation of energies of the signals) may be differently forevery pixel of the synthesized image and extraction of any noise andinter-modulation products of the signals of such images.

In another aspect of the invention the source 2 transmits MMW/SMMWradiation 6 towards a diffuser 7, which, in turn, diffusively scattersthe radiation towards 8 an observed object 9 and/or an area ofinspection. This diffuser 7, firstly, may be used for formation ofoptimal degree of spatial coherence of the radiation, being incident onthe observed object situated in the field of view of an imaging system.Said optimal spatial coherence of the object illumination radiation canallow to form enhanced quality images even for a case when the objectspecularly reflects the incident radiation.

Such peculiarity of the illumination system increases possibilities ofthe system 1 for forming images of high quality due to decreasing ofimage noises which where caused with high spatial coherence ofradiation. Such noises are manifested in the form of random spatialdistributions of speckles (random aventurine spots exhibiting differentbrightness). Some modification of illumination system based on usage ofthe diffuser allows to decrease influence of strong specular reflectionsof the radiation from the object (so called glint effect).

The usage of such a diffuser may be effective both for aquasi-monochromatic radiation and for a multi-frequency radiation. Inthe last case the system of illumination permits more essentially todecrease coherent noises in formed images, since in this case both thespatial coherence and temporal coherence of backlighting radiation maybe decreased.

In accordance with the present invention a diffuser is a constituentpart of diffuser illuminator of imaging systems operating in millimeterand sub-millimeter wave ranges. The diffuser illuminator is intended foran illumination of an inspection (or observable) area with encodedspatially-incoherent radiation, which is primarily generated by at leastone compound source of radiation in the millimeter and sub-millimeterwave range, designed in the form of a limited amount of sets ofindependent constituent radiation sources, radiation every of which ischaracterized with all or a part of values of correspondent radiationphysical features being distinct from all or only a part values ofcorrespondent radiation physical features of every other constituentradiation source provided such constituent radiation sources belong tothe same said set. Diffuser of the diffuser illuminator being situatedapart from said compound radiation source to be illuminated with itsradiation and, then, to scatter said radiation towards said inspectionarea. The diffuser is designed to be capable to decrease spatialcoherence of the diffuser-scattered radiation. Said constituentradiation sources are designed (with function) with their ability toencode emitting radiation, particularly by means of any kind ofradiation modulation, therewith radiation of any constituent radiationsource is encoded distinctly from radiation of any other constituentradiation source whatever either said sources belong to the same saidset or to different said sets. Moreover independent constituentradiation sources belonging to the same said set illuminate preferablythe same spatial portion of said diffuser, but independent constituentradiation sources belonging to different said sets illuminate preferablydifferent spatial portions of said diffuser.

The diffuser may be designed in the form of a set ofspatially-distributed point-like cells, encoding incident radiation bydistinctive manner from each other owing to a distinctive modulation oftheir scattering properties. The cells are disposed along an arbitraryshape of underlaying surface, which should be designed of the requiredshape. Therewith constituent radiation sources being grouped in theirsets are disposed relatively the diffuser by such a manner to providemaximal range of angle of incident of diffuser-scattered radiation inthe inspection area.

Besides, a scattering cell may be designed in the form of themirror-reflecting element, mounted on a particular piecewise-platesubstrate, therewith, the different mirror-reflecting elements aredesigned with an ability of a displacement with respect to acorresponding general substrate by distinctive from each other way andare at a displacement value, which is less than a half of the shortestwave of the illuminating radiation.

For a realization of said displacement of said cells they are fastenedto movable magnetic cores of inductive current coils (

) or to piezo-elements, powered by means of occasional currents of bymeans of currents, regularly varied in time and by distinctive way. Thediffuser scattering cell may be designed in the form of liquid crystalcell, besides, optical properties of various said independentmesomorphic liquid crystal cells of such a diffuser are varied in timeeither occasionally or regularly and distinctively from each other.

The diffuser may be designed in the form of a rotating reflector withrandom reflecting surface or in the form of set of relatively smallconstituent reflectors with said random reflecting surface, each ofwhich rotates with respect to the own axis of rotation and each of whichis illuminated by own said set of the independent partial constituentsources of radiation. The constituent reflectors and correspondent saidpartial constituent source sets are disposed in space by such a way toprovide maximal range of angles of radiation incidence into theinspection area.

The diffuser may be designed in the form of phase antenna array, a phaseshifter of each element of which is designed with a function ofdistinctive in time variations of phase of passing or reflectingradiation.

Besides, said independent partial constituent radiation sources may bedesigned with an ability of generation of radiation, which is linearlypolarized in the first space direction, but said scattering cell isdesigned in the form of the independent quasi-optical switcher ofradiation, representing a set of spatially-distributed independentconducting elements, disposed on a plane substrate, besides, theadjacent conducting elements are preferably coupled by means ofnon-linear elements in the first space direction, besides, a modulationof impedance of the non-linear element results in a modulation ofamplitude or phase of radiation wave front, impinging normally on such aswitcher and said depending on a resistive or capacitive character ofthe impedance of said non-linear element.

The dissipating element may be designed in the form of antenna, loadedby impedance. Each antenna, loaded by impedance, represents by itself atleast two conducting antenna portions, connected between one another bymeans of non-linear element for providing with an impedance load andeach of which is equipped with the correspondent contacts for applyingto said impedance load a bias voltage and/or a modulating signal forcontrol the impedance value of this load.

In accordance with embodiment the diffuser illuminator for imagingsystems in the millimeter and sub-millimeter wave ranges, intended forilluminating an inspection area by encoded spatially-non-coherentradiation, comprises at least one source of radiation in the millimeteran sub-millimeter wave ranges, and a diffuser, positioned in at adistance from the radiation source and intended to be illuminated withthe radiation of said radiation source and, then, to scatter for thisradiation toward the inspection area, the diffuser is designed in theform of a set of spatially-distributed radiation-scattering cells, beingcapable to perform modulation, for example amplitude modulation, of theradiation, scattered by them, by distinctive from one another way.

Besides, a scattering cell of the multi-cell diffuser may be designed inthe form of an independent quasi-optical set of conducting elements, theadjacent conducting elements belonging to the same set are connectedwith each other preferably in the first direction by means of connectingmeans, having the first impedance in the first state when the connectingmeans are not conducting and having the second impedance in the secondstate when the connecting means are conducting, the conducting elementsbelonging the same said spatially-distributed set in combination withthe connecting means being in said first state have such a negligiblecharacteristic impedance in response to incident radiation beingpolarized in the first direction that the incident radiation issubstantially reflected and in combination with the connecting meansbeing in said second state have quite high characteristic impedance inresponse to incident radiation being polarized in the first directionthat the incident radiation is substantially transmitted through such aquasi-optical switcher (switch) cell. P-I-N diodes may be used as saidconnecting means which are conducting when are directly biased andnon-conducting when inversely biased. Time varied modulation signalapplied to extreme specific points of said set of said conductingelements provide time-varied biasing of all said connecting means ofsaid set and as a result provide modulation of radiation scattered bysach a diffuser cell. Frequency of modulation signals may be differentfor different diffuser cell that provides distinct encoding of partialradiation components scattered by the diffuser.

In case of realization of a diffuser which is capable only to destructspatial coherence of incident radiation, various sufficiently smallspatial portions of the diffuser scatter (pass through/reflect)correspondent constituent components of radiation which are mutuallyincoherent in phase. Therewith receiving apparatus of imaging system hasto provide summation of radiation energy in every formed image pixel atleast for characteristic time duration of mutual changes of relativephases of said constituent radiation components (being scattered withthe different spatial portions of the diffuser), for time duration therelative phases have to be changed in range from 0 to 6.28 (2p) radians.

In one of the embodiments the diffuser 7 represents immovable as a wholearray of electronically or optically controlled spatially-distributedscattering point-like (quasi-point) cells 10,11,12,13. The term“point-like” cells means, that their angular sizes, at which each ofthem may be observed from any spatial point of the inspection area orthe object, is essentially less than angular sizes of own diffuser as awhole upon its observation from the same said spatial point ofobservation.

This diffuser consists of specially designed spatially-distributedmultiple point-like scatterers, scattering properties of which may becontrolled by means of electronic or optic (optic-electronic) way inorder to scatter incident radiation components independently from oneanother and additionally to encode the formed partial components(constituent components) in a distinctive manner due to distinctivemodulation of their scattering properties.

Besides, all the partial constituent radiation components or only someclusters of them may be distinctly encoded, therewith, the diffuserprovides with a phase independence of said partial constituent radiationcomponents, scattered by diffuser cells for all the components (each ofsuch partial constituent radiation components is originated withseparate scattering diffuser cell).

It should be noted that said capability of distinct encoding of theradiation components may be determined largely with receiving part ofimaging system, namely, with resolution capability of its decoding units(their possibility for distinctly distinguishing the radiationcomponents having closely-spaced parameters of their encoding).Practically such a diffuser decomposes spatial-coherent radiationincident upon the diffuser into multiple partial constituent radiationcomponents exhibiting distinct angles of their propagation intoinspection area (depending on spatial locations of correspondentdiffuser cells 10,11, “originating” correspondent partial constituentradiation components, relative to surface of the object 9).

In limiting case each of such components may be distinctly encoded todistinctly label by different modulation signals supplied to each ofsuch a point scatterer cell (or in other words spatial portion) of thisdiffuser.

Thus, it is appeared an ability to differentiate the radiationcomponents, illuminating the observed object at various incident angles.The distinct radiation components will create partial images, each ofwhich may be distinctly received by receiving apparatus, transformed inthe digital form and distinctly stored into a digital memory for theirfollowing processing to synthesize a resultant image, at that, beforesaid synthesize procedure useful information content in said partialimages may be extracted while noises and interferences in the partialimages may be reduced up to their elimination by different techniques ofimage processing _([L1]) (it may be also realized in analogous blocks ofimaging system less effectively and less full, but sufficiently rapidlyand less expensively). Said aggregate of processing procedures which canbe applied to the partial images for an obtaining the resultant image ofthe object, as any other aggregate of processing procedures, that isbased on the usage of an obtained set of different partial images andthat leads to an improvement of the resultant image, obtained as aresult of such a processing, further is (referred as) terminologicallydetermined as an “combination”.

For example, a number of said partial images or only some portions(fragments) of such images, causing destructions of quality of theresultant synthesized image, may be easily identified and then theirinfluence is electronically decreased in real time, for example byelimination from said synthesis procedure. The latter will lead tosignificant improvement of visual quality of such resultant images andto an enhancement of their informational contents, being achieved as aresult of the processing. The informational resultant images of highquality can be created, for example, by means of weighted digitalaveraging of various partial images (this summation of the partialimages may be realized also partially or in whole by means of analogousway, as it was described for case of analogous accumulation of energy ofmulti-frequency partial images). At that it can be averaged such partialimages, which are formed by partial radiation components exhibitingvalues of distinctive radiation features which are the same (or being insome range of variation of values of these physical features). Thelatter represents an interest for indicative revealing of peculiaritiesof radiation reflected by the observed object, for example, such aradiation physical feature may be a linear polarization, or its carrierfrequency, or angle of incidence (or some range of the angles) ofradiation on a surface of the observed object. During the averagingprocedure it can not be used those partial images and/or only itsportions which cause destruction of the resultant image. Such partialimages or only their portions may be formed by partial radiationcomponents which are reflected from the observed object or only fromsome parts of them by specular manner. Aforesaid procedures of thesynthesis summation may be of interactive type, so the procedures may bestopped only when coherent speckle noises and other factors, destructinga quality of the resultant image will be decreased to required level.Aforesaid processing procedures may be realized both in a time ofimaging procedure when the partial images are formed and after theimaging procedure in time of post-imaging digital processing of thepartial images. Such a posteriori processing procedures are able toreveal all the most important details of concealed objects.

As it was above-mentioned, an electronic or optical control allows tovary various physical properties of the dispersed radiation 8, forexample, of statistical character and such as a degree of spatialcoherence. The dispersing elements 10, 11 of the diffuser 7 may bedynamically (in real scale) arranged into groups (by means of variationencoding-modulation parameters of the elements without any changes ofdecoding (e.g. demodulating units) units of the imaging system in such amanner, that the radiation, dispersed by each of such a cluster, will becharacterized by own (dynamically varied) value of angle of impinging(incident) onto the observed object. Each such a cluster obtains its owncode in such a manner, that the radiation, dispersed by such a clusterafter its interaction with the object, may be individually decoded outof the composite radiation of the composite source on a side ofreceiving means of the imaging system (at time of receiving).

The diffuser 7 directs a radiation on the object 9. Besides, the objectis positioned in field of view of focusing element (lens) 14, by meansof which the radiation 15, dispersed by various portions of the object9, is focused (forming the object image) in an area of position ofreceiving device 16 (further it is designated as an “RD”) on thecorresponding receiving elements 17, 18, 19 (if they representthemselves a immovable multi-element receiving array), or in thosespatial points 17, 18, 19, which are periodically scanned by one or somereceiving elements of this receiving device.

Characteristics of radiation 15, reflected, dispersed or absorbed by theobject, depends on differences in material, surface, texture and volumeof the object 9. If the object is homogeneous one, then the radiation 8may be dispersed by various portions of the object 9 by means of variousway. For example, if the object includes plane metallic portions, thedispersed radiation 15 will include both the mirror and diffusioncomponents, from which the mirror render a destructive action on aquality of formed images.

In general case a receiving portion of the receiving device (RD)represents by itself an array of MMW/SMMW antenna receivers, each ofwhich is associated with an individual receiving channel oftransforming, amplifying and partial of whole decoding of receivedsignals. The antenna receiver is understood in that sense, that thisreceiver transforms a signal of electromagnetic radiation into a signalof electric currents, induced on its conducting elements. Besides, thisantenna receiver may be both in the form of a classic antenna receiver,when it transforms a signal of radiation into its current form withoutof variation a frequency contents of this signal (in other words,without of variation of the signal structure and carrier-frequency(frequencies), and in the form of antenna receiver, in terminals ofwhich there is mounted a non-linear element (for example, a Schottky'sbarrier diode-), realizing a non-linear transformation of said (current)signal and separating its envelope (in this case this non-linear elementplays a role of amplitude detector of input signal). If onto such anantenna-coupled non-linear element it is quasi-carrier optically appliedon a par with the input signal additionally an oscillator signal inconsequence of non-linear transformation of corresponding inducedcurrents on the antenna by such an element, it is separated a signal ofintermediate frequency, and such an antenna-linked-non-linear elementplays a role oh input mixer. Thus, the amplitude detection or evenheterodyning of input signals of MMW/SMMW is realized immediately onsuch an antenna elements without additional rectifying or mixingradio-technical units with the transformation of the input signal intothe electrical signal of the intermediate frequency or signal of theenvelope, which may be further processed in sequential electronic unitsfor a decoding and separation of information about an object fromcorresponding encoded components of these signals.

Complete two-dimensional set (matrix) of said multi-component signalsforming a corresponding matrix of pixel signal of an obtainedmulti-parameter MMW/SMMW image in this case may be obtained also inconsequence of spatial scanning one-element antenna receiving element(or of other limited quantity of ones) in a plane of focusing of thecorresponding imaging system focusing means, In this case a set ofindependent (encoded) signals and their contributions in any pixel(picture element or element of image) of correspondent partial matriximage for such a scanned imaging system is determined by composition ofradiation signal (consisting from correspondent encoded and generallyfeature-varied radiation components), received by the correspondentantenna element in the corresponding spatial point of scanning.

Besides, such a radiation will enter in antenna element from thatportion of observation zone, on which this antenna element “looks” (isquasi-optically aligned by means of focusing element) from said spatialpoint, a characteristic size of said portion of a space will bedetermined in the given case by means of sizes of aperture of thecorresponding focusing element (lens, mirror and so on). A size of theinput aperture of the focusing element is greater, its spatialresolution is higher and said side of the space, resolved by it, isless. It is clearly that said two-dimensional spatial set ofmulti-component (which may be named as a N multi-parameter image,wherein the number N is a quantity of distinctly encoded/ and furtherdecoded components in each of said signals) may be hardware separated orsoftware separate into analogous two-dimensional spatial sets,comprising only similarly encoded/decoded components. Such sets are inessence partial one-parameter (exhibiting a particular value or set ofvalues of radiation component features) images, simultaneouslyregistered by means of system, wherein each parameter responses on thatphysical feature and its value, by which a radiation is characterized ofillumination, encoded by distinctive way in the above-described system.The above-said multi-parameter formation of images relates naturallyalso to a case of the usage of non-scanned two-dimensional receivingarrays. In this case it is possible an obtainment of multi-parameter“instantaneous scene”, and it is importantly for imaging of fast movingobject. Besides, it is importantly to obtain instantaneously a largescope of information, allowing precisely and rapidly to estimate maskedobjects. The procedure encoding (including modulating of its parametersor features) of partial radiation components means in the embodimentthat each of the component is associated with a particular label whichallow to identify by decoding distinct decoding (e.g. distinctdemodulating) the electrical signal, corresponding to said distinctlyencoded component, amongst other such signals in every receiving channelof the receiving means and individually to measure of its averagedintensity or other parameters/

The receiving channels of transforming, amplifying and decoding ofsignals of the receiving device (means) may have any realization for aprovision with a necessary level of amplification of the signals and fortheir decoding (including decoding exploiting frequency demultiplexingof signals being encoded by their frequency multiplexing) includingrealized by scheme of super-heterodyne receiver or even a directamplification with a sequent amplitude detecting of radiation,amplifying on the bearing frequency.

A polarization grid 20 may be additionally positioned between thereceiving device RD 16 and an element 14 (lens, mirror and so on),focusing MMW/SMMW radiation, inside a field of view of which it islocated the object 9. The polarization grid, positioned on the opticalof the focusing element for separation of linear-polarized components ofthe radiation, may be provided with a rotation means, varying itsposition around the optical axis for an separating both the co- andcross-polarization radiation components (it is also possible anelectronic realization of the array, picking out both the componentwithout a mechanical rotation). It will allow to control any variationsin polarization properties of the radiation, reflected from the object.Besides, the object may be illuminated by means of linear-polarizedradiation with mutually orthogonal polarizations of independent partialradiation components. It will give additionally an ability to obtain anycomponents of coherent array (or polarization grid) for revealing anypeculiarities of the radiation depolarization by the object.

A second such a polarization grid 2 may be positioned before thediffuser 7 only for a separation of the components with the linearpolarization out of the radiation, dispersed by the diffuser.

An information about the multiple partial images, obtained afterdecoding of RD 16 signals, is supplied to a processing means (processor)22, which process the information in order to create a synthesized imageor a set of synthesized images as a result of pre-processing partialimages and/or their combining (or combining of their portions). Adecoding of the signals may be also realized by the processor onlydigitally. The image (images) is (are) directed onto a display 23. Thepartial images are in digitized form and are loaded into a computermemory, and it determines digital numerical capabilities of processingof such images.

It is possible an embodiment, in accordance with which the processor 22is also connected to the source 2 and/or the diffuser 7. Such a feedbackmay be used in order to control operations of the source 2 and/or thediffuser 7 in combination with principles of encoding of spectral andpolarization information in the source 2 and/or angular and/orpolarization information by the diffuser 7. It may be realized, inparticular, in order to obtain a minimal necessary level in a zone ofthe observation independently for each partial radiation, and itprovides with a minimal possible level of the observed objectbacklighting power. A control response may be also rendered on thediffuser in order to minimize mirror reflections of radiation from theobject in a real time in a process of imaging.

A deletion or at least minimization of distortions in images, obtainedby means of radiation, possessing of a high coherence, by which all theartificial sources of MMW/SMMW radiation are practically characterized,may be realized by means of creation (generation) of numerousstatistically independent partial images for various values of physicalfeatures of correspondent partial radiation components forming each ofsaid partial images, with following creation of resultant image as aresult of processing of them. One of effective methods of such aprocessing is an additive summation of energies of such images (possiblewith a various relative contribution of each of partial images and/ortheir portions) for a formation of the resultant image of improvedquality. As such a distinctive radiation feature it may be an angle ofthe partial radiation incidence on the object surface while savingunchangeable other physical features of these partial radiations or, inother words, of these radiation components. As another such a physicalfeature it may be a carrier frequency of radiation components (theangles of the radiation components in such a case may be the same as, bythe way, also the other physical features of these radiation componentsmay be unchangeable as well). These partial images are represented inFIGS. 2-5. Regular wave fronts of said partial radiation components arerepresented as 24, 25, 26 before their interaction with the objectsurface. Their destructed fronts, appeared as results of the last theirinteractions with the object rough surface, are represented as curves27,28,29 (FIGS. 2-4). Curves 30, 31, 32 (FIGS. 2-4) relate tocorresponding partial images, formed by the fronts 27, 28, 29 in a planeof the receiving device 16 by means of the focusing element 14. Asummation of various partial images 30, 31, 32 by means of their energyaccumulation in each of corresponding elements (pixels) of said imagesduring a time of image exposition allows to obtain improved sum imagesof the object 9, one of which is represented by a curve 33 in FIG. 5upon a realization of said procedures of summation it should beconsidered that the partial images may be

practically spatially similar ones (practically the same ones), ifcorresponding radiations, forming them, have closely the same values ofdistinctive radiation fatures a^(h) _(i) (wherein i—index, showing whatphysical feature is varied, for example, if i=1, a frequency is varied,but if i=2, an angle of backlighting by a point source is varied;h—index characterizing a value of this feature, for example, for thefrequency of 94 GHz this set i=1 and h=1, for the frequency of 95 GHzthis set i=1 and i=2

so on). In FIG. 6 there are shown curves 34 and 35 of such partialimages, values of physical features of which are closely to α^(h)_(i)≈α^(l) _(i) (for example, the frequencies are closely the same ones(in case of variation of radiation frequency as the radiation features),or angles of backlighting (illuminating) are closely the same ones (incase of the illuminating angle variation). Their summation image 36practically repeats initial partial images and possesses the same a lowquality and correspondingly is not similar to a required “ideal” image37. In FIG. 7 there are shown partial images 38, 39, values of physicalfeatures of which are different from one another by a value {overscore(α)}_(i), i.e. α^(h) _(i)−α^(l) _(i)≈{overscore (α)}_(i), upon whichthese images for the object under observation become statisticallydistinctive ones. If mediate energies of such images (or their distortedportions) are the same ones (i.e. there is no an effect of mirrorreflection), a summation of such images (or their distorted portions)results in an obtainment of resultant images of improved quality 40.However, even in case of a satisfaction of condition α^(h) _(i)−α^(l)_(i)≈{overscore (α)}_(i) in case of mirror reflection of one of partialcomponents a partial image 41, corresponding to its, preferably will bemore bright and correspondingly with more average energy (or energy ofpart of the portions, comprising the mirror reflections) in comparisonwith the partial image of diffusely reflected radiation 42, besides,their sum image will repeat a mirror reflection 41 in spate of thepresence of other diffusive images in general sum. It is understood thatin case of a separate receiving of partial images their summation shouldbe realized with various weights for an obtainment qualitatively sumimage of type 40. In this case a system allows to realize atransformation of sum “mirror” (i.e. comprising a prevailing mirrorcomponent in all or a part of pixels of image included in some imageportions only) images of bad quality into sum diffusive-type images ofimproved quality, and it was not obtainable formerly.

Another but technically more complicate realizable way consists in acreation of multiplicative images in accordance with FIG. 9, an energyof which in each pixel is proportional to a square of module from aproduct of amplitudes of two various partial images. A dynamic range ofsuch multiplicative images will be practically the same. Besides, ifdiffusion images in corresponding products are different 42, 44, thecorresponding multiplicative images will be also different and theirsummation also results in the resultant image 45 of good quality. Suchan approach may decrease significantly requirements to a dynamic rangeof receiving apparatus, besides, it is of course required acorresponding technical realization of separation such multiplicativesignals or their sums. In order to obtain a multiplicativedifferent-frequency image it is possible to illuminate the objectequally by two sources, the frequencies of which differ by a frequencyshift, but a mediate frequency is swept. Besides, a frequency of shiftmay be stabilized under hardware control by means of synchronous phasingwith a phase of stabilized reference signal by means of phase-lock loopblock diagram, an error signal (control voltage) of which is feed on acontrol electrode of one of such a source (VCO). (One of realizationswill be shown below). On a receiving side after an amplification of sucha doublet spectral signal its difference signal (corresponding to amultiplying of amplitudes of this doublet spectral components, which maybe easy realized by means of corresponding non-linear element-diode inthe first after amplification (which may include also a like frequencyshift both the spectral components of the doublet in consequence ofheterodyning) cascades in an amplitude detector) will correspond with aconsidered multiplicative image in a corresponding its pixel, receivedby said antenna. The difference of frequencies of the doublet spectralcomponents may be regulated, and it allows to determine an optimaldifference in frequencies for the partial images. Another ability in arealization of the multiplicative images will be discussed further inview of the realization of modulated diffuser. In this case a variedphysical features will be an angle of the object backlighting(illimination) by means of radiation, primarily dispersed (scattered) bymeans of point disperser (scatterer)-diffuser element (cell).

A widening of effective frequency band of an illuminating radiationresults in an increased number of spectrally distinctive, but thenstatically independent speckles of images. All it leads to a decrease ofthe image time coherence. Within limits of the present system it ispossible the usage both the analogous or optically-similar integrationof signals of partial images and digital (including weighted) summationof partial statically independent images.

As it was mentioned, one of the physical features of the backlighting(illuminating) radiation is its frequency.

As a multi-frequency source it is understood a source, which emits aradiation at least at two various frequencies. Spectrally distinctivepartial images may be created only upon using a radiation, consisting ofat least two essentially distinctive spectral ranges. It is essential,since wave fronts of radiation for components, having spectraapproximately with the same spectral content, will be transformed by theobject 9 and will be projected then by the lens 14 on the RD 16 bysimilar way, and it results practically in the same partial images,which do not give an improved image upon their summation, and inverselyordinary some distinctive partial images are sufficient in order toobtain an image of improved quality in consequence of their summation.

For a demonstration of practical influence of the above-describedprocedures of the summation of the partial images on a capabilities ofidentification of the objects in FIGS. 11-13 there are representedresults of numerical simulation of the object (pistol), having outerlikeness of shape and character sizes of details with such typicalobjects, for an observation of which systems for imaging in themillimeter range are mainly worked out. Upon the simulation there wereremoved all factors, that are capable to induce speckle-structure inimages, in order to demonstrate a destructive influence only Gibbsoscillations and capabilities of their action overcoming. In themillimeter range in contrast to an optical range the spatial Gibbseffect, conditioned by a scantiness of passing band for spatialfrequencies by a focusing element, is capable seriously distort theobtained images. In FIG. 11 there is represented a distribution ofintensity, accumulated during a time of exposition in an one-frequencyspatially coherent image for the frequency of 70 GHz. (It is supposedthat the wave front impinges on the object surface normally, and besidesvarious portions of the object are quasi-plane ones). This image isdistorted by means of unremovable oscillations of the intensity, whichare typical for the Gibbs effect and essentially distort its quality,besides, a character of distribution of brightness specks in FIG. 11corresponds to a structure of specks in images of real pistols, whichare experimentally obtained and have a bad quality. However an image,which is synthesized (or even combines) by means of accumulation ofpartial images, independently obtained for five frequencies 68, 76, 84,92 and 100 GHz (see FIG. 12) makes such a five-frequency imagepossessing of essentially improved quality, increasing simultaneouslyits information content, that is sufficient for the object recognizing,having a single meaning. In FIG. 13 there is represented a scale ofgradations for a single level in corresponding elements of the images,shown in FIGS. 11 and 12.

But a simple decreasing of number of frequencies is not capable toimprove automatically a quality of image The Gibbs effect appears, whenspatial frequencies in the image of the object exceed a band of passingspatial frequencies upon imaging. It is stated that preferable frequencystep equals to N=3-15 GHz and more. Further decreasing of the frequencystep will result in a summation of practically the same distributions inthe intensity of partial images and in increasing of signal absolutevalue, but not in essential limiting of oscillation limitations.

A frequency interval for an effective decrease of speckles in image, asit is known, is determined by a depth of heterogeneity of the objectsurface, and also it preferably makes up a value of 3-15 GHz and more.

There are below represented various embodiments of the multi-frequencysource 2. Besides, the multi-frequency source may be represented in theform of partial independent sources, having fixed narrow-band spectrallines of radiation. They may be waveguide or monolithic (carried out inaccordance with integral monolithic technology) embodiment of Gunn'sdiode or avalanche transit-time diodes (ATTD), a frequency of which maybe any practically in a wide portion of the MM range. If outputs ofthese sources, as in other also any other, are loaded by frequencymultipliers, which divisible increase frequencies of radiation (withcertain conversation losses), the range of frequency coverage by suchcombined sources extends to the upper limit of SMMW range. Suchgenerators may be combined in such a manner, that the lines of theircombined radiation (by means of output antenna of the same emittedradiations in free space) may be consisting of both the one spectralcomponent (singlet) and two narrow spectral components (doublets) andalso several components (multiplets). The difference signals ofcomponents doublets (multiplets) may be phase-synchronized by means ofsignal of support frequency-stabilized source(s), and it is importantfor a provision of high sensibility and high dynamical range of thereceiving device of imaging system.

Depending on a realization of sources-oscillators the radiations ofpartial sources may be distinctively encoded (by means of modulating byamplitude or phase modulation). When the various partial sources areencoded, their radiation may be easy identified an the receiving side.

A spectral width of the lines may be sufficient wide, if there are usednoise oscillators as partial sources.

A multi-frequency source may be designed as an source of swept (variedwith respect to a frequency) radiation or as their combination, swept inthe same ranges (a doublet embodiment) or in various ranges. Theirhardware realization may be in the form of lamps of backward wave (LBW),lamp of running wave (LRW), FYG oscillators (based on the usage of filmson the iron-yttrium garnet), outputs of which are loaded by thefrequency multipliers. The ranges of tunable frequencies in these casesmay attain to tens of gigahertz.

It should be analyzed separately an effectiveness of said “noise”sources of radiation. In a number of cases Their “noisiness” in thelimits of 1-15 GHz for the effectiveness of imaging systems may beinsufficient (from this standpoint they may be quite considered asquasi-monochromatic sources). However, such sources may represent aninterest, if for a formation of images it will be used industrialstandards of imaging of MM images in the form of MM cameras, inputstages of which have a wide band of operational frequencies, and theyare not modified for receiving narrow band or phase-stabilized paireddoublet signals.

Such cameras, as a rule, is worked out for a receiving a passiveradiation and they excellently operate in free space under condition ofhigh MM intensity temperature T, when the objects are contrastilluminated from above and from a side of upper semi-sphere by means of“cool” sky at T=70 K and from below from a side of “warm Earth'ssurface” at T=300 K. Owing to fundamental laws on thermodynamic balanceof radiation in closed systems, in accordance of which MM intensitycontrast of observed zone in closed rooms is insufficiently high forthem, they would not be used effectively inside of rooms (wherein allthe procedures of inspection properly occurs). In this case suchMM-chambers may be used effectively, if the spatial coherence ofradiation of noise sources is preliminarily destructed by the diffusers,various realizations of which are below described. As it follows fromthe above-adduced information a width of band of operational frequenciesof solid-state noise sources, which does not exceed 1-5 GHz, isinsufficient for an improvement of quality of images owing to amulti-frequency. If there are used vacuum super wide band noise sources(with a width of 10-20 GHz and over), in them separate spectral bandsare not independently controlled, therefore there are beyond aregistration and correction peculiarities of distribution in free spaceand diffuser dispersion, an absorption in the object and reflection byit as well as a receiving by receiving array separate components invarious spectral ranges, and it narrows the capabilities of such asystem. Besides the effect of the mirror reflection of this radiationfrom the object may whittle a broadbandness of radiation, thatilluminates the object.

In this case it will be a preliminary dissipation of broadband signal bymeans of diffuser, destructing its spatial coherence, besides, variousand differently AM modulated beams of such a radiation should preferablyilluminate various spatial portions of such a diffuser. It provides witha selectivity of receiving device with respect to mirror objectreflections of the radiation, dispersed by mans of various portions ofsaid diffuser. Besides, if a band of operation frequencies is sufficienthigh, it may be used said illuminating beams, characterized by means ofspectra, which are localized in various spectral sub-ranges (andcorresponding generators), positioning inside of this band. Besides, aradiation in such beams should be distinctively AM modulated, forexample, by means of broadband pin-modulators. In this case parametersof the radiation are optimized both for the effective using ofamplifying portion of the receiving device in order to improve itssensibility and for a provision of spectral and spatial selectivity withrespect to the radiation, illuminating the object, in order to formimages of improved visual quality.

A generalized block diagram of adaptive MMW/SMMW system based on usageof wide-band multi-frequency source of MW/SMMW radiation with acontrolled level of intensity and spectral content of its radiation isshown in FIG. 10.

Mainly this self-adapting imaging system includes following five basicsubsytem

1) the wide-band focusing means (FE) (e.g. lens) 14, intended for thefocusing MMW/SMMW images in its focusing plane;

2) the receiving device 16, including:

a) a receiving antenna array 46 (for example, the two-dimensionalstaring immovable receiving array, or, for example, a mechanicallyscanned 1D array), intended for spatial (2D) sampling of radiationdistribution of image focused by said focusing means 14 by receivingarray antenna elements 47,48 and converting portions of radiationreceived by the antenna elements during said sampling into corresponding2D matrix set of electrical signals (which will be used for formingpixels of resultant images and their visualization);

b) unit 49 being fed from receiving antenna array 46 which consists ofmultiple receiving channels each of which intended generally foramplification, frequency downconversion and partial or total decoding(demodulating) of signals, received by said receiving array (eachreceiving array antenna element 47, 48 of array 46 hasis fed to own saidreceiving channel, which together forms a corresponding receivingelement 17,18 of the RD 16);

and further digitizing of output signals of unit 49 receiving channelsby feeding them tot;

c) unit 50 of multiplexers, which is fed by said signals of unit 49 andfeeds them to

d) unit 51 of analog-digital converters which perform aforesaiddigitizing of the signals;

e) unit 52 of local oscillators-heterodynes, generating heterodynesignals for providing down-conversion of the received signals intointermediate frequencies of amplification in unit 49 (if suchdownconversion is needed);

3) unit 53 for controlling various modules included in different unitsof the imaging system, and also for forming multiple partial images fromdigitized signals of unit 49 and digital processing of set of formedpartial images; the unit 53 includes image preprocessor 54 (performingformation of partial images received by receiving array 16 and theirprimary processing), interface unit 55 (for transferring differentsignals between units of the imaging system), host processor unit 56(controlling the imaging system as a whole) and unit for processing ofresultant images and further their visualization on screen of display57.

4) unit 2 of radiation sources 3, 4, 5, each of which consists ofseparate radiation generator 58,59,60, (which can be called as radiatingelement) each of which is provided with own radiation (AM/PM/FM)modulating module 61,62,63 (an output each of the generator 58,59,60 islinked with an input of the corresponding modulators 61, 62, 63),besides, each of the modulators is controlled by means of correspondingcontrol module 64,65,66.

Each generator has either own antenna system 67, 68, 69 for directingthe generated radiation in a free space, or a common antennae system 67(for example in case of waveguide embodiment), in this case the signalsof the generators are united in one general waveguide, connected to saidantenna system by means of unit 70 of guided directional couplers,besides, a one part of antennae systems 67-69 may illuminates thediffuser 7, but another part 71 illuminates immediately an area ofinspection (observation). In this realization it is essential that eachradiation source 3, 4, 5 may be provided with own attenuator 72, 73, 74,included, for example, in each channel of the source in series betweenthe generator (which can be oscillator of any type, mercury lamp,point-like termo-heater ans so on) 58, 59, 60 of this channel and itsmodulator 61, 62, 63. Furthermore, an output of the generator (forexample, reference number 58) of each source 4 is linked with an inputof own attenuator 72, an output of which is linked in series with aninput of the corresponding modulator 61. Besides, each attenuator 72 (aswell as attenuators 73,74) is positioned under control of thecorresponding control module 64 (65, 66) of the corresponding channel 4(ref. numbers 5, 6), besides, the control module 64 (65, 66) controlsnot only the attenuator 72 (73, 74), but also and the modulator 61 (62),and properly the oscillator 58, (59, 60) (for example, in case ornecessity of sweeping the lasts with respect to a frequency and so on).

It allows to control a level of radiation power of the correspondinggenerator 58, 58, 60, partly or completely a spectrum of its radiationand modulation characteristics of the modulating module 61, 62, 63 and aradiation power of the corresponding source of the radiation, emittingin a free space through the corresponding antenna 67,68,69, which isregulated by the corresponding attenuator 72, 73, 74, (so that a levelof the radiation is controlled on the base of information, obtained froman analysis of partial images by the units 53, 56 in accordance with theselected criterion),

5) unit 75 of electronically controlled diffuser, which may consist ofown diffuser 7 and control module 76 for controlling and drivingdiffuser cells 10, 11, 12, (including controlling of diffusercells-modulating signals) if the diffuser is realized with a capabilityof its control (In another embodiment the elements 10, 11, 12 of thediffuser 7 may be controlled immediately by the processor 56).

In case of another embodiment of the source a feedback will compriseother sub-systems, corresponding to a functional destination of such asource with an optimal construction for their characteristics.

In particular, a heterodyne source 54 and radiation sources 3,4,5 (moreexactly, in this case their generators 58,59,60 are voltage-controlledoscillators) may be connected to each other by phase-lock loops toprovide phase-coupling of their signals (as it will be shown below),providing with a mutual spectral shift (a frequency of their differentsignal) of their signals by a value, corresponding to a intermediatefrequency of corresponding control frequencies of an amplificationchannel of the unit 49, but their difference signals aresynchronously-phased by means of harmonic signal(s) of high-stabilizedreference oscillator(s). It provides with a high frequency stability anda spectral purity of the intermediate frequency signal, arising at ashift of a useful signal, received by the corresponding receivingelement 46, and with a signal of the heterodyne 52, stabilized by meansof phase-lock loop. It, in turns, allows to realize a narrowbandfiltering of the signal, already beginning from a cascade of thephase-lock loop, providing with a rejecting of noises and significantlyincreasing a sensibility and dynamic range of the RD 16 of system inwhole.

A broadband spectrally controlled source of the MMW/SMMW imagingincludes at least two partial sources of MMW/SMMW radiation with anessentially distinctive spectral composition of emitted radiation (oronly with central frequencies) or with at least one source, but it isfrequency-swept in sufficiently wide spectral range. It is morepreferable a source construction, in which various spectral componentsare emitted essentially from the same spatial point 9 a phase center) orfrom points, which are near to each other. For a waveguide realizationthe same horn may be used for a radiation of all the spectralcomponents. In this case, however, each frequency channel should beisolated from one another in order to exclude a mutual influence.

In order to resolve this problem there is used a set of waveguidedirectional couplers. A width of spectrum, radiated by means of horn,will be restricted by means of a passage of corresponding waveguidesystem. If it is necessary more wideband radiation, a source shouldinclude a limited quantity of point-similar horns, which are frequencydistinctive ones and have own set of partial sources for each horn. Incase of integrated realization of the partial sources the set ofdirectional couplers is not necessary. Each partial source includes anindividual radiating antenna (horn), which is integrally linked with thesource 2.

FIG. 10 shows a general block-diagram of self-adapting system and it isintended only for a demonstration of one of sufficiently generalrealization of a functional device. As it was above-mentioned, in thesystem each of the partial radiation sources 3, 4, 5, of the radiationsource unit 2 may have an independent control, since the control module(driver) 64, 65, 66 for each of corresponding generator controls alsothe corresponding modulation module 61, 62, 63 of these oscillators andown oscillators (which may have any nature of embodiment (fixed withrespect to a frequency, swept with respect to a frequency, noise onesand so on), and also their attenuators 72,73,74, besides, it has aspecified electrical connection with the interface module 55 andcorrespondingly with the processor 56. An interconnection of thefeedback mechanism allows to provide with an ability of determination anoptimal spectral distribution of multi-frequency MMW/SMMW source foreach determined object an for a corresponding environment.

A control of average intensity (or other characteristic of theintensity) for each partial image (including images, which essentiallydiffer by a frequency) by means of block of the feedback allows todetermine the optimal spectral distribution in all the spectral rangesof the source in scale of real time. The offered approach is capable totake into consideration any frequency dependence for a propagation,permeation, reflection, adsorption and detection (mixing) of radiationsignals in order to obtain an image of the best quality.

A multi-frequency approach may be successfully realized, if it is usedRD, that is sensible to a radiation in all the spectral range of theused source, and quasi-optical elements, used for imaging, are alsobroadband ones.

In most cases an average of the intensity signals along all the set ofpixels of each partial image is necessary in order to use correctly theintensity signals in order to estimate a correct level of the intensityin such an image. It takes a place owing to a speckle structure, thatpresents in each partial image, and in consequence of this fact a valueof the intensity in one any pixel of such an image (or in their smallquantity) can not be representative one.

In general case, at first the partial images should be formed by thefocusing element 14, received and transformed into the form of array ofelectrical signals, separately amplified, decoded by the unit 49 andtransformed into the digital form by means of units 50,51 of thereceiving device 16, then they should be processed by the unit 53 andonly after that step an information may be used for a calibration ofradiation sources of the unit 2 of sources and for control the diffuser7. Such a calibration should be repeated in accordance with variedconditions of the reflection and adsorption for the observed object. Thecalibration of the intensity of sources (and the diffuser) may becarried out by means of different ways. For example, various spectralsub-ranges (radiated by separate partial sources) may individuallyregulated sequentially in time. A sequence of operations of a systemcalibration method will be described with a reference to FIG. 10combined with FIG. 1.

A quasi-monochromatic radiation of each of partial sources of theMMW/SMMW radiation 2 are selected under condition that they will easydistinctly detected by a receiving side. This condition consists in theamplitude or frequency modulation of carrier frequency, probably, incombination with a doublet realization of the spectral composition ofradiation. This radiation is directed either onto the object 9 by meansof antenna system 71, or initially onto the diffuser 7 and after then itis dispersed by means of the antenna system 67, 68, 69 into thedirection of the object 9. The radiation, reflected and dispersed by theobject 9, then is formed in the form of this object 9 image by means ofthe focusing element 14 on the receive array 46 of the receiving device16. Each antenna element 47, 48 of the receiving array 46 works out thecorresponding first electrical signal, and in general case each such asignal consists of set of composite differently encoded partial signals,corresponding to partial radiations of said partial sources 3, 4, 5(dissipated in a number of realizations by the diffuser 7, carrying outan additional encoding of the radiation, which then should bedemodulated (decoded) by corresponding demodulating block diagrams ofthe unit 16 after a corresponding amplification and processing. Soprocedures encoding of multiple radiation components allows to separateones at receiving side by their decoding so to identify value ofcorrespondent radiation feature and to measure intensity of theradiation component (or other its parameter).

In process of the amplification and processing the corresponding signal,received by the separate receiving element 46 in the RD 16 may be mixedwith the signal of heterodyne 52 of unit of the heterodynes, having afrequency, practically coinciding with a frequency of the correspondingspectral sub-range of the signal, and it takes a place (if a principleof heterodyning is used in the receiving block diagram of amplificationchannels). Further the signal may be amplified by means of controlfrequency of the unit 16 cascades, it may pass the step of secondaryheterodyning (if necessary, its parallelism may be deleted (by means offrequency-selective blocks various partial signals have various spectrallocalization) on inputs of blocks of decoding devices (PM, FM, AMdemodulators of decoders of another type), signals out oh output ofwhich may be directed into inputs of electronic circuit diagram,separating an envelope of decoded signals (the simplest resolution ofproblem is the usage of amplitude detectors, normally realizing anon-linear transformation in order to separate the envelope of thetransformed signal) and by sequential filers of low frequency or otherintegrators of the envelope energy (which is proportional to an energyof the signal, received by the antenna 47 and decoded by thecorresponding decoder. Said integrators should have a corresponding timeof the energy accumulation (in particular, the time of the accumulationnaturally should be more than a time of the most long time of mutualphase deviation of components, which are a part of the signal, receivedby antenna, and which are passed through the corresponding independentdecoding circuit). Such components may appear in the signal inconsequence of a destruction of spatial coherence by the diffuser 7 onthe base of incidental, incidental-distinctive or distinctive modulationof various spatial portion of the dispersing diffuser 10, 11, 12. Ansummation of such components my means of said signal integrator allowsby analogous way in common accumulate the energies of these components,which are proportional to an energy of corresponding radiationcomponents, suppressing simultaneously any interferential signals bymeans of their averaging in time. Thus, the output signal of theintegrator will be proportional to that group of components ofradiation, received by the considered antenna, which turn out the samedecoded ones. If a discrimination of decoding device is variable, forexample, by means of width variation and a variation of center frequencyof corresponding band-pass filters in a frequency depended decoders, theoutput signal of the integrator will be proportional to a total energyof greater or smaller group encoded (including distinctly) components,totally hitting in a band of such a decoder. Besides, it is realized ananalogous accumulation of energy of both the phase-incidental andequally-encoded components and the components, encoded by various way(which also may be additionally by randomly-phase-modulated), but whichare equally decoded by the given receiver. A number of independentdecoders in each channel of signal amplification and processing,associated with the given antenna in considered case determines aquantity of possible independent partial images, each element of each ofwhich is proportional to an energy of said equally decoded radiationcomponents, occurring in the given antenna in the considered interval,associated by means of the focusing element with the correspondingspatial dispersing a radiation portion of the observed object or thearea of observation. If, for example, there is a portion of surface ofthe dispersing diffuser corresponds to said radiation components,equally decoded, and is associated with them, the elements ofcorresponding partial image will be responsible for the image, obtainedupon an illumination of the object or area of observation by means ofspatially non-coherent radiation (naturally with a correspondingfrequency and polarization) disposed and having spatial sizes, equal tosizes and a position of a corresponding portion of the diffuser. Thelast condition determines a mediate angle of impinging of the spatiallynon-coherent radiation components on the object, illuminated by them,which are a part of equally decode signal. The last condition is veryimportant upon a reveal of flashing components of a radiation, dispersedby the object, for sequential their removal or for a proportionaldecrease for an equalization with the components, reflected the sameportion of the object, but at other angles of illumination. The ispossible a technical realization, at which all the independently encodedcomponents (being even independently encoded for all the spatially smallportions of the dispersing diffuser, determining a radius of spatialcoherence) may be independently decoded, and corresponding numerouspartial images may be obtained and, for example, loaded into a memory ofdigital means in order to their weighted summation by digital way.However, partial images, obtained for radiation components, dispersednearly positioned dispersing portions of the diffuser will be physicallyand practically equivalent ones (their speckle structures will be thesame ones), and it leas to a deletion of their speckle structure upontheir summation. In this case too much number of the partial images willlead to unjustified usage of system resources (hardware, temporal an soon), and said regulation of a discrimination of decoders is capable tooptimize the system with respect to its effectiveness and cost. It isalso understood that upon a complete or partial accumulation of signalsof possible partial images a signal amplified after an amplitudedetector an comprising several groups of partial signals, should passthe step of filtering in order to accumulate the energy of signals ofpartial images and the step of excluding of all the inter-modulationproducts. In case of partial analogous accumulation of the signals ofthe partial images, the signals only of that part of the partial images,which are subjected to the analogous accumulation, should be directedonto the amplitude detector and integrator. It may be realized (as itwas mentioned), for example, by means of band filtration of thesesignals by virtue of a difference in their modulation frequencies or byany other way.

If there is used a swept radiation source, a time ofaccumulation-integration of signal, obtained in various instant time,for which the swept sources are characterized by varied physicalfeatures of radiations, generated by them, should be at least more orshould be equal to a maximal time of radiation sweep by value of thecorrespondent physical radiation feature. In case, when a physicalradiation feature is the carrier frequency of the radiation,

-   -   it should me more than time of frequency sweep and reciprocal        quantity from a minimal frequency interval between nearest        spectral components, which is present in general spectrum of the        emitted radiation.

Besides, if at least two swept generators are simultaneously used, theirradiation should be independently encoded. If finally an analog-digitalconverter is used for digitizing signals from output of said stage(inbtegrator) of said receiving unit to be loaded in digital memory Itappears simple possibility for time demultiplexing of the signalscorresponding to the same encoded radiation component but which exhibitsdifferent values of radiation physical features in different instanceswhen the features are scanned in time, by digital processing means(processor) being programmed in such a way to extract independently (toindependently receive) the correspondent signals because the ADC willsample the signal sequentially in time and correspondent secondarysignals corresponding to different values of the features may beseparated by correspondent processing procedure. The correspondentpartial images independently for each selected value of the radiationfeature for all the range of scanning will be received independently,therewith said integrator should be optimized for the receiving only thesignals, encoded independently, without taking into account an effect ofsummation of partial images for various values of swept radiationfeature.

In general case the signals from output of said integrating filters arekeyed into the input of a corresponding analog-digital converter (ADC)of unit ADC 51 by means of the unit 55 of multiplexers (or eachintegrator has own ADC) and then after a digital transformation furtheris processed correspondingly by means of the pre-54 an main processor56.

In case, when the unit 16 completely realizes the step of decoding ofsignals, entering in composition of each of signals, received by thereceiving elements 47, 48 of the array 46, then a two-dimensional arraywith a dimensionality, which is equal to the dimensionality of thereceiving array 46, and the elements of this array are filled bysecondary signals to form the corresponding partial image. Saidsecondary signals equally decoded and exhibiting the same set of currentvalues of the correspondent radiation features of the correspondentreceived radiation component (or that is equivalently, by theirinformation-significant parameters, for example, by a value of averagespectral density or in more general form, by an integral power of thedecode signal) separated out of the corresponding received signalassociated with the corresponding receiving element like 47 by itsdecoding (demodulation) and time demultiplexing (demultiplexing is usedif the radiation feature is scanned). Besides, other such arrays,comprising equally decoded signals, but of other value of correspondingcode (or a parameter of modulation) and/or distinct set of the samecorrespondent values of correspondent radiation features will form otherpartial images.

It is understood that a frequency decoding and encoding (in other wordsfrequency demultiplexing in case of encoding of radiation components byfrequency multiplexing) may be realized also totally in the digital formby means of realization the digital fast Fourier transformation (FFT)over corresponding digitized outputs temporal signal (comprisingfrequency encoded components), transformed into the digital form bymeans of the corresponding ADC of the ADC unit 51 and further processed.

An algorithm of self-adaptation of system for decreasing a level ofbacklighting and adaptive suppression a part or all the mirrorreflections of the object is worked out in such a manner that tocalculate a mediate value of energy of partial image or otherstatistical value with respect to all the elements (or requiredportions) of formed partial images and on the base of this informationto regulate the system units. Repeating said procedure for each of thepartial source 3, 4, 5 of the unit 2, a multi-frequency source isregulated with respect all the range of the frequencies, used in thegiven application, besides, there are revealed those individuallymodulated and regulate elements 10, 11, 12 of the diffuser 7, thedispersed radiation by which causes mirror flashes in the partial imageafter a reflection from the corresponding portions of the object 9. Thismethod is a calibration method of sequential type. Here factors ofweighting (a coefficient of regulation a power of the partial source 3,4, 5 by means of the attenuators 72, 73, 74) are created for each of thefrequency ranges besides, there are created sets of information for theregulation of said elements of the diffuser in the same spectral ranges.These factors of weighting and said sets may be further immediatelydirected into the control modules 64, 65, 66 in order to regulate anintensity of each source radiation. The intensity of each source may besupported constant one, but a factor of the weighting and thecorresponding set for each frequency interval may be used for its usagein a software upon a creation of improved image by means of digitalmethods.

Another method for the system calibration is a method of parallel type.In this case there are simultaneously radiated all the partial sources3, 4, 5. The partial source for each frequency interval in this caseshould be distinctly modulated by means of modulated signals, forexample, by the signals, generated by the modulation units 61, 62, 63.The signals of the units 64, 65, 66 control each source of the sourceset 3, 4, 5. All the modulated multi-component radiation of the sourcesis directed either onto the object, or onto the diffuser 7 through thecorresponding antenna system 67, 68, 69, then onto the object 9 (seeFIG. 1). The radiation, reflected and dispersed by the object 9, then isfocused on the elements of the receiving array 46 of the unit 16. Thesimultaneous demodulation of signals of each frequency interval by meansof amplification and pre-processing modules 49 allows to reveal astatistical information about each of the partial images, and it alsoleads to the calibration and to the obtainment of the weightingcoefficients. Again these coefficients (factors) may be used either in asoftware, or by means of a direct usage by the elements 72, 73, 74 andby other elements of the radiation source and the diffuser 7.

Since a principle of improving of image quality consists in an summationof statistically independent speckle images which comprise a determinedspatial information about the imaged object, any additional approach inthe independent obtainment of such images will complementary providewith further improvement of quality of the resultant images. Suchadditional partial images may be obtained on the base of peculiaritiesof a movement of the observed object. It is known that even relativelysmall variations of orientation of the object 9 surface, which may begeometrically sufficient complicated with respect to an entrance pupilof the focusing element 14, may lead to an essential variation of adistribution of relative phase shifts, originating in wave front ofpartial radiations, which are dispersed by different portions of thissurface (these phase shifts turns out various ones for various spectralranges, an it increases capabilities of multi-frequency method) thatcauses variations in the spatial speckle structure of the correspondingpartial images.

Since the determined spatial information about the object in slightlyreoriented objects will be practically the same, (it is suggested, thata frequency of frames in the imaging system is sufficiently high, thatallows to fix small variations the object angle upon a movement of itscarrier-individual in the field of view if the imaging system, which iscoincidence generally with a field of view its focusing element) and atthe same time their speckle structure will by sufficiently different, aset of such images (obtained in accordance with a method of fastchanging of frames) is an additional set for a procedure of accumulativeimprovement jf quality of the resultant image. This technique isattractive one, when the system allows to make a recording of numerousframes in process of contraband detecting, owing to the fact, consistingin that an individual-carrier of contraband practically always makesautomatic movements by own body, even when stands and particularly in aprocess of own movement. These movements allow to make a set ofinstantaneous frames of partial images with various speckledistributions for the nearest angles of the observed object. A speed ofobtainment of such frames-mages should be sufficiently high one in orderto provide with a speed of obtainment of such frames-images should besufficiently high in order to provide with a “photographing” of evensmall variations in the object angle. These conditions may be satisfiedfor SI equipment, wherein the frame speed is more than 1 frame insecond.

Any common usage of adaptive in time or in space or decomposition intothe corresponding partial components of radiation (in case ofdisintegration both with respect to a wide spatial spectrum and withrespect to a wide spectrum of carrier frequencies it may say about asource of “white” radiation) in combination with the above-describedmulti-frame technique will create a plurality of effects, leading to animprovement of quality of images of the observed objects owing tomutually independent characteristics of the corresponding partialimages. An adaptive complex MMW/SMMW radiation of illumination createsimages of high visual quality, firstly, owing to that an increasednumber of statistically independent images may by simultaneously usedand, secondly, owing to that their combined usage may realized by meansof digital methods on the base of used computer system.

It should be noted that in the declared method it is realized a simpledigital summation of partial images, comprising partial radiantcomponents, dispersed by means of spatially differentdispersers-elements of the diffuser. In this case an information aboutmutual phases between the wave fronts, responsible for a forming ofdifferent partial images, will be naturally lost, as it is required fora spatially-non-coherent illumination. A procedure of summation partialimages by means of digital means is equivalent one to a non-coherentaccumulation of radiation by means of integrating analogous receivingcircuits. Of course, a number and a form of partial images should not bemore than necessary for goals of correct detection. An summation ofpartial images in the above-mentioned procedure may be used both ofdigital and analogous types simultaneously in that or another degree inaccordance with the destinations of particular imaging system.

Since a signal, obtained by each receiving element of the RD 16 (or, inother words, a signal, forming each pixel of such a multi-parametersynthesis combined image) is temporal (varying in time). The dimensionof, matrix sets, dimension (structure and dimensions) of this array willbe determined by means of dimensionality of the receiving device 16receiving array) of such time signals, having a determined finalduration (this duration is determined by means of minimal frequency,comprising in such a signal in accordance with the Shennon's theorem)will comprise all the information (including a dynamics of the observedobject path) about a multi-parameter image of the object, obtained byquasi-optical way.

Every signal from the matrix set consists of signal parts each of whichassociated with different set of values of radiation physical featuresof source radiation if at least one of the physical features of thecomposite radiation is time varied. Said signal parts may be extractedfrom correspondent signal, for example, by demultiplexing with formingcorrespondent second electrical signals

On the other hand, such matrix set of the signals, by means of timemultiplexing of said signals of said matrix set of the signal into asingle broad-band communication signal, may be transferred by means oftraditional broadband communication systems in any place of location ofmore powerful computer for fast and full-scale processing.

In order to send such signals from all the elements of the receivingarray, an algoritm of the multiplexing may be used in such a manner thatthe signals from various elements of the RD 16 are sent (are connectedinto united communication channel in various time intervals (at firstthe signal of the i-element of the RD, then the signal from the(i+1)-element and so on).

In FIG. 14 there is represented a waveguide realization of MMW/SMMWmulti-frequency point-like source (all the frequencies are radiated fromone phase center) with a controllable spectral density of radiation fora self-adaptive imaging system, operating in scale of real time. Anywaveguide partial sources of MM range (back wave tubes, Gunn's diode andso on) may be narrowband with a fixed frequency; swept in narrow range,in wide range, any broadband MMW/SMMW source like noise sources orothers and so on) may be used in such a composite source. Each of thepartial sources consists of own waveguide realizations (waveguidegenerators) of oscillators 58, 59, 60 (that in sequential drawings maybe mutually replaceable 77 by 58, 78 by 59

so on, if it is not stipulated that the shown generator has no waveguiderealization. Each generator operates on the own frequency or in the ownrange of frequencies, if it is an voltage-controlled oscillator (VCO),the frequency of which varies upon a variation of the voltage of acontrolling supplied to controlling electrod of the VCO. Outputs each ofwhich are waveguide in series (in series by means of waveguideconnection) connected to own one-directional isolators 80, 81, 82,which, in turn, are waveguide in series connected with the radiationattenuator 83, 84, 85 (for example, realized on PIN-diodes), outputs ofthe partial oscillators 58, 59, 60, which are outputs of thecorresponding radiation attenuators 83, 84, 85, are waveguide in seriesconnected to the separate radiation modulator (any of type ofmodulation, e.g. f AM—amplitude modulation or FM—frequency modulationmodulators type) 61, 62, 63, outputs of which are connected to a generalwaveguide, besides, the directional couplers of the set 70 of thedirectional couplers are used for some said modulators 62,63. A generalwaveguide 86 is connected to a general antenna, through with the signalsof the generators 77, 78, 79 are radiated in a free space.

Each partial source 3, 4, 5 has correspondingly own control unit 64, 65,66, each of which (64) consists of own power sources for oscillators 87,unit 88 for modulation control and unit 89 for radiation attenuationcontrol, if a frequency of the oscillator is swept, it may beadditionally used a unit 90 for frequency scanning control, each ofwhich is connected to corresponding controlling inputs of correspondingpartial radiation sources (for example voltage-controlled oscillator).Control signals is provided into units 87, 88, 89, 90 under control ofthe center processor 56 via the interface unit 55 (the last unit mayinclude additionally a unit-synchronizer, realizing a generalsynchronization of operations of all the units of the multi-frequencygenerator, and if there is no such units the same synchronization may berealized by the processor 56).

For simplicity, there is only small number of the partial sources 4, 5,6, which are shown in FIG. 14. It is preferably that this set of sourceswith distinctly various frequencies and a spectral content would besufficient one in order to cover all the spectrum of interest, goinginto a waveguide pass band of used type. In order to replenish aspectrum composition it may be used a similar multi-frequency source,used for a waveguide of other type.

Each oscillator 58, 59, 60 includes the own radiation attenuator 83, 84,85 in order to regulate separately a radiation intensity (orcorrespondingly a spectral density) of each partial source.

Each attenuator 83 is controlled by the own control unit 88, which, inturn, is controlled by the processor 56 in accordance with an algorithmof self-adaptive imaging. In case of the usage of partialfrequency-swept source, which is swept upon a sufficiently broad ranges(which are different for various sources) sweep-generator(s) is(are)connected to a control electrode of the corresponding oscillator 77.Meanwhile each unit 90 is also controlled by the processor 56.

Each partial oscillator 58, 59, 60 may be switched-off from the

| waveguide 86 by means of the own attenuator 83, 84, 85 in order toallow an independent calibration of each channel.

Besides, an intensity of each frequency sub-range may be exactlyregulated by means of the same waveguide attenuators 83,84,85(functionally corresponding to the attenuators 72, 73, 74 in FIG. 10),each of which is under control of a pre-processor via the own controlunit 88. If it is used frequency sweeping module, the mentioned modules(attenuator, sweeping oscillator and so on) should be controlled by theprocessor 56 in accordance with the self-adaptive algorithm for thesources of such a type. In this case the corresponding unit-attenuator83 should be dependent with respect to a time and should be controllablewith respect to a synchronization with the swept oscillator 77 for aprovision with a required regulation of the radiation spectral densityall over the broadband range. A maximal width of such a spectrum shouldnot be more than a pass band of the corresponding waveguide. If it isrequired a radiation with a band broader width, it is necessary to use aset of sources with a corresponding waveguide characteristic.

Partial sources may be united between each other by means of additionalcontrolling block diagrams for an additional control of radiatedradiation and their mutual spectral frequency. The partial sources,additionally united may be sources of doublet or multi-doublet radiationwith separate circuit diagrams of control the frequency shift and mutualphases between components of the doublet/multi-doublet (beingdoublet-pair of two nearly positioned singlet spectral lines offrequencies, the multi-doublet represents by itself a several of suchsinglet, which are grouped close by each other in some cluster).Besides, it may be attained a novel quality in a modulation of suchdoublet signals, stabilization of their difference frequency (as well asa locking in phase of their difference signal (formed by means of mixingsignals of the doublet components) with a high stabilized signal of anadditional oscillator (for example, crystal oscillator) or its harmonic.The last condition is very important, since the mentioned differencesignal will be obtained in a consequence of it in channels ofamplification of RD after the first amplitude detection (by anynon-linear element-diode) additionally amplified (and perhapsfrequency-shifted after heterodyning equally for both the doubletcomponents) doublet signal. And the doublet signal will possess ofhigher spectral purity and stability (and correspondently low phasenoises), corresponding to a spectral purity (due to narrow-band spectralline) and stability of the mentioned reference stabilized signal of thecrystal (quartz) oscillator. Besides, frequencies of themselves partialMMW/SMMW oscillators may be characterized by very bad stability, also astability and spectral frequency of any heterodyne oscillators of thereceiving device are not important, since their phase noises are addedin both the components of the doublet signal by means of identical wayand they will be excluded at the step of amplitude amplification.Furthermore, the difference signal is secondary detected by means ofsynchronic detector, the support signal in which is taken from thementioned crystal oscillator. The offered diagram of generation andreceiving of doublet signal provides with a record high sensibility andnoise immunity (and even a covert capability, if a carrier frequency ofsources is varied additionally and by means of special way) of areceiving, since it secures a limit high instantaneous narrow-bandnessof such a technique and correspondingly a low level of noises of thereceiving device. A doublet representation of spectral lines securesalso a simplicity of radiation encoding of set of sources with variousfrequency and polarization. Since a frequency shift may be arbitrarilylarge, but a stabilization of the difference frequencies (which aredifferent for various doublet sources) extremely high, a number of suchpartial components (with various sets of values of said physicalfeatures) may be arbitrary great, since a spectral distribution of thedifference frequencies, obtained after the amplitude detection, will beprecision stable. Furthermore, as a matter of fact there is offered anovel method for a FM modulation by means of modulation frequency and/orphase of the difference signal of the doublet components, which may besynchronically phased by any FM/PM signal.

A realization of device of such a stabilized doublet source may be suchas follows. Two practically identical MMW/SMMW oscillators, for example,the oscillators 78,79 (in the given case of waveguide embodiment, but,perhaps, and of monolithic embodiment), one oscillator 79 or both theoscillators 78,79 are voltage-controlled oscillators (VCO), i.e., itsfrequency may be varies upon a variation of the control voltage) arepositioned in such a manner that they will generate a radiation in freespace by the same way (or even from one phase center)—in the given caseit is realized by means of the usage of said two directional couplers ofthe coupler set 70 for combining of energies of signals of both theoscillators in the common waveguide 86 and their radiation will pass ina free space through the common horn antenna 67.

Smaller portions of the energies of the signals of each of oscillators78,79 are derived by means of directional couplers 91,92 and areseparately connected to outputs of the oscillators 59,60 via thecorresponding isolators 81,82 into a mixer 93 for a formation of signalof difference frequency; from an output of the mixer 93 the signal ofthe difference frequency through a band filter 94 is fed to the firstinput 95 of phase detector (or in other words, phase discriminator) 96;to the second input 97 of this phase detector 96 it is fed a signal ofreference oscillator 98 (for example it may be a signal of the abovesaid stabilized crystal oscillator (or its low harmonics) a signal ofphase mismatch (error) from an output 99 of the phase detector via afilter 100 of low frequencies (which is used for a decrease of phasenoises in the difference signal) is fed to a control input 101 of theVCO 79 as a signal of the phase mismatch of difference and referencesignals for its elimination. The considered loop of the phase-lock loop(PLL) diagram (of phase automatic frequency control) provides with aphase synchronism of the difference signal and the spectrally cleanstabilized signal.

As it was mentioned, greater portions of energies of the oscillators78,79 via the corresponding directional couplers of the unit 70 of thedirectional couplers are united in the general waveguide 86 and areradiated in a free space via the general antenna 67.

A block diagram of pair oscillator of doublet signal 102, providing witha spectral narrowness (cleanness) of the difference signal may be addedby a module of automatic search and locking-in a frequency of thedifference signal by means of a preliminary feeding of scanned voltage(for example, from the unit 90) to the control electrode of VCO before amoment of the difference frequency locking-in by means of the consideredloop of PLL with a sequential switching-off of the scanned signal aftera statement of such a locking-in. There are also possible otherrealizations of the doublet source with the stabilized differencefrequency of the higher spectral cleanness.

In order to improve the receiving device parameters (its sensibility anddynamic range) in each amplifying channel of the last it may be added asynchronic detector, an input of which is electrically connected toblock diagram, separating and amplifying the signal of the differencefrequency from the doublet signal, received by antenna, besides, to thereference input of the synchronic detector it is fed a signal of theabove-considered stabilized crystal oscillator. If such a transceiver isused in applications, associated with realizations of the MMW/SMMWimaging systems, the signal of the crystal oscillator may be fed to theinput of the synchronous detector by means of coaxial cable through aphase shifter, compensating a phase increment of signal in the cable,since oscillators and receivers are positioned at some distance.(Besides, at the output of such a parametric detector it will beseparated an envelope, which is proportional to an intensity of thedoublet components, receive by the antenna, cutting an information aboutdispersing properties of the object surface. In place of the phaseshifter it may be used a circuit diagram with an obtainment ofquadrature components at the synchronic detector output, in this casethe envelope will be also obtained).

In case of the usage such a transceiver for transmission of informationsignal, which may be controlled by one 62 or phase opposite by both themodulations 62, 63 of a coupled doublet oscillator 102 (see FIGS. 15,17, 18), at the mentioned reference input of the synchronic detector ofthe above-considered receiving circuit diagram it should be fed asignal, preliminary separated out of corresponding additional diagram offrequency selection of the receiving device, which is separated out ofcomplete spectrum of the received communication doublet signal and whichspectrally corresponds to a signal of said crystal oscillator. Besides,a phase of the separated reference signal should be shifted by a valueof the phase depending on a type of the used modulation. in order toprovide with proper selection of the doublet signal modulation in atransceiver it should be provided the form of general signal at thetransceiver output, upon which said support signal is expressed in theform of separate spectral line. In order to improve an effectiveness ofthe receiver operation, the receiver should be added by a heterodyneVCO, a intermediate frequency of which corresponds to the frequency ofthe support signal, and which is synchronized by means of system of thephase automatic slight adjustment by said signal, separated from thegeneral spectrum. Besides, an output of the VCO through the phaseshifter is connected with the support input of the synchronic detector.

The above-considered transceiver provides with a high multiplexing ofcommunication channels in MM+MMW/SMMW ranges, since it provides with atough spectral localization (with an accuracy up to tens Hertz and less)of the difference information signal, arising in the receiving deviceafter a non-linear detection of doublet simulated signal. Besides, thecentral frequency of the difference signal may be arbitrary small up toseveral MHz and arbitrary high up to 1 to 1.5 GHz and over, since it isdetermined only by a frequency of the stabilized source 98 signal. Ifthis source is frequency or phase modulated, another possibility of thedifference frequency oscillator 102 appears. Another possibilityconsists in an addition (for example, by means of summing operationalamplifier or any other quick-acting summator) to an error signal, fed toan input of a control electrode 101 of the VCO 79 some more and amodulation signal, an information in which consists in a variation ofits amplitude (voltage).

A frequency spectrum of this modulation signal is deflected, taking intoaccount a condition of its suppression by the filter 94 in a compositionof the difference signal, separated by the mixer 93 and the filter 100in a composition of the erroneous signal, an output of which is fed toone of inputs of the summation device (to the second its input there isfed a modulating signal, but its output is electrically connected withthe control electrode 101 of the VCO 79. In this case the doubletdifference signal will be frequency-modulated with a great deviation ofthe difference frequency, besides, a central non-modulated component(line) of spectrum of the difference frequency signal (a non-modulateddifference signal of the corresponding doublet signal, obtained upon theabsence of said modulating signal) will be synchronically phasedstabilized by means of the crystal oscillator 98.

A multiplexing of signals and their broadbandness is important insystems of high speed wireless inter-computer communication and in othercommunication applications. Besides, a stabilization themselvesoscillators of the MMW/SMMW range may be how like bad one. It is all themore important that the stabilization of the MMW/SMMW sources is verydifficult and expensive one.

A principle of improving of visual quality of the object images,destructed by the coherent noises of the radiation source includes ansummation of numerous speckle images of the object, besides, each ofspackle image should be statistically independent (in the present casethe question is a spatial distribution of the speckle structure image).As it was shown above, the variation of frequency of the radiation,which may be radiated from the same point, results in an obtainment suchstatistically independent speckle images, but their sequent summation(accumulation) allows to obtain a decrease of speckles in the resultantimage, and it promotes an improvement of visual quality of images.

It is possible to vary a position of point disperser (diffuser) withrespect to the illuminated object without a variation of illuminationradiation frequency. These variations of the spatial position of thediffuser element result in a variation of angles of impinging on theobject surface, and it, in turns, results to a variation ofcorresponding optical way of this radiation from a dispersing radiationof the diffuser elements to the nearest points of the object surface.Owing to the letter phase differences in wave fields, dispersed by meansof the mentioned nearest points of the object, will be redistributed,causing variations in the speckle structure of the corresponding partialimages.

As it was shown in FIG. 10, the coherence radiation from the source 2 isdirected onto the immovable, but electrically (or optically) controlleddiffuser 7, which is intended for a destruction of the spatial coherenceof radiation (or for said destruction and an additional partialencoding, or for a whole encoding, that results in said destruction ofthe spatial coherence), impinging at it. In this context “the immovable”means that the diffuser does not rotate or it does not move as a whole(although upon a number of realizations in principle its separateportions may move). Within the bounds of one aspect of the presentinvention the diffuser may be designed as antenna-array one. Such adiffuser represents by itself a spatially distributed set of antennae,paired conductive elements of each of which in the point of input port(input) are connected to each other by means of non-linear element(capable to vary itself impedance under action of control signal that iselectrical and elliptical one). The antennae may be positioned on theplane in the form of two-dimensional array with distances between theadjacent antennae, which are no more that several lengths of waves for aprovision of complete destruction of the spatial coherence of thedispersed radiation. Besides, the antennae may be located at the morecomplex surface (for example, in the form of paraboloid) for aconcentration of the radiation and for an uniform illumination of thearea of inspection by it.

One of such antennae is shown in FIGS. 15 and 16. A band of frequenciesof such antennae is selected in accordance with the MMW/SMMW radiationof the source 2. Impinging on spatially-distributed array of differentlymodulated such antennae, the spatially coherent radiation 8 (see FIG. 1)is transformed into the dispersed spatially non-coherent radiation 15with a controllable degree of spatial coherence (besides, thecomponents, dispersed by differently modulated antennae appearadditionally distinctly encoded, but the impinging radiation appearsdecomposed into various components, distributed variously in the area ofillumination, and which are independently encoded by means ofelectronically controlled elements of the diffuser 7 array).

In FIG. 15 there is shown a section of antenna 103, which is loaded bymeans of impedance. In this realization each antenna represents byitself at least two conducting antenna portions 103 and 104, connectedbetween each other in a point of the antenna input by means ofnon-linear element 106 for providing with the antenna load, which iscontrollably varied by the impedance of this load 105, and each portionof the antenna is shifted by itself contacts 107, 108, through which avoltage of the voltage shift (biasing signal) and/or a modulation signalis fed at the non-linear element 106 for control a value of theimpedance of dispersing element.

If the portions of the antenna are disposed on one side of a dielectricsubstratum, on which there are located the antenna portions 103, 104 andthe non-linear element 106, but contacts 107, 108 are disposed on theother side of the base, each element 107, 108 has itself conductingconnection with the corresponding antenna portions 104, 105 through saidbase. In FIG. 16 it is shown the considered element with a frontalposition. In this realization as an antenna it is selectedantenna-butterfly 104, 105, characterized by a broad-bandness ofoperation frequencies.

As a non-linear load it may be the Schottky's diode, p-i-n diode, acorresponding transistor (including field-effect transistor) or othernon-linear element, providing with a non-linearity of conductivitybetween its electrodes, which are included at the antenna input, besidesas a non-linear element it also may be selected a photoconductiveelement (photo-diode, photo-transistor an so on), in this case a controloptic modulation signal proceeds from a side of the substratum or from aside, that is opposite with respect to substratum.

When an impedance of the load 106 is completely matched with animpedance of the antenna 104, 105 input, an impinging radiation isessentially dispersed by such an antenna (by means of “almost mirror”way), as it was shown in FIG. 17 by an indicatrix of diffusion 109. Inthat case, when the load is completely mismatched with the antennaimpedance, the indicatrix of diffusion, being initially “almost mirror”,becomes “diffusive” 110 (FIG. 18), besides a level of diffusion ofradiation abruptly decreases. Upon a variation of the impedance in timethus an amplitude simulation of the dispersed radiation occurs.

By means of load switch between values, matched and mismatched by meansof impedances, a wave field, dispersed by such an antenna element 103,may be made of controlled and modulated one. This switch may be realizedby means of application of electrical or optical modulating signal tothe dispersing element.

The impedance load 106 of the antenna 104-105 as well as principles ofits modulation may be different with respect to a nature. For example,the loads may include the Schottky's diode or a bismuth bolometer oreven two-or three-terminal micro-mechanical switches (MEMS). The loadsmay be also photo-controlled from a photo-conductor to aphoto-transistor.

There are various approaches for a modulation of the antenna load. Aresistance of the bolometer, for example, may be varied owing to aresistor heating and cooling or by means of modulation of low-frequencyelectrical signal, for example, applied to the load 106 via the antennaelements 104, 105. The modulation signals may be applied to the antennaelements via band filters of nigh frequency in the form of catchers, forexample, including inductive elements, worked out in such a manner thatthe electrical modulation signals pass through them, but the signals ofmillimeter radiation are completely blocked.

Another approach for a modulation of the load may be realized on thebase of principle of photoconductive load modulation by means of opticalmodulation signal, which may illuminate the loads through correspondingopenings in an array substratum. A principle of optical modulationprovides with advantages, consisting in that circuits do not require anylow-frequency electrical circuits, which are necessary in order to feeda signal to a modulated element.

Besides, the impedance of non-linear element may be preferably ofcapacitive character (a capacitive portion exceeds considerably aresistive portion for example, varactor Schottky's diode), and in thiscase the dispersed radiation will have a various phase of radiation,dispersed by it, (accidental or regular depending on a character ofmodulation signal) upon a variation of impedance element value, but acombination of such arrays will accidentally vary a phase of variousspatial portions radiation, dispersed by means of wave front array,i.e., will destruct its spatial coherence.

If the non-linear element is preferably resistive one, its modulationresults in an amplitude modulation of radiation, dispersed by it. Sidecomponents of the radiation, dispersed by various way by modulatedantennae will have different shift of frequencies, making the dispersedradiation distinctive way frequency-encoded one, allowing to carry out adecoding of each component of the radiation, received by a receiver byhardware-simple way.

In order to improve an effectiveness of the diffuser dispersion thediffuser 7 may be designed as a diffuser 111 in accordance with FIG. 19in the form of spatially distributed set of independent quasi-opticalradiation switches (IQORS) 112, 113 of radiation, disposed on a generalsubstratum 114 of plane or piece-plane shape (in whole the piece-planesubstratum 114, which is shown in FIG. 19 an at which there are disposedthe IQORS 112, 113, . . . may have a shape, that is optimal for theobserved area illumination). Each of the IGORS may carry out anamplitude or phase modulation of radiation, dispersed by it by means ofvarious way (by means of accidental, regulatory-distinctive way or bymeans of way. Combined with two previous ways) depending on modulatingsignals, and it may function both with the radiation passing and withits reflecting depending on the realization.

Besides, a scattering IQORS cell of the multi-cell diffuser may bedesigned in the form of an independent quasi-optical set of conductingelements, the adjacent conducting elements belonging to the same set areconnected with each other preferably in the first direction by means ofconnecting means, having the first impedance in the first state when theconnecting means are not conducting and having the second impedance inthe second state when the connecting means are conducting, theconducting elements belonging the same said spatially-distributed set incombination with the connecting means being in said first state havesuch a negligible characteristic impedance in response to incidentradiation being polarized in the first direction that the incidentradiation is substantially reflected and in combination with theconnecting means being in said second state have quite highcharacteristic impedance in response to incident radiation beingpolarized in the first direction that the incident radiation issubstantially transmitted through such a quasi-optical switcher (switch)cell. P-I-N diodes may be used as said connecting means which areconducting when are directly biased and non-conducting when inverselybiased. Time varied modulation signal applied to extreme specific pointsof said set of said conducting elements provide time-varied biasing ofall said connecting means of said set and as a result provide modulationof radiation scattered by sach a diffuser cell. Frequency of modulationsignals may be different for different diffuser cell that providesdistinct encoding of partial radiation components scattered by thediffuser.

So each such an independent quasi-optical switch IQORS (see FIGS. 20-24)represents by itself a spatially distributed set of independentconducting elements (CE) 115, 116, 117 of relatively small sizes, whichare disposed quite at a plane substrate 118, besides, the adjacentconducting elements 115-116, 116-117 and so on are preferably connectedbetween each other in the determined (first) spatial direction by meansof connecting elements 119, 120, 121 (which are really non-linearelements of any nature being able for operating in frequency ravge ofilluminating radiation, above-described in connection with the antennadiffuser array (it may be Schottky's diodes, the varactor Schottky'stdiodes, photodiodes, P-I-N diodes and so on), each of which may beswitched by biasing from its high-impedance (first) state and itslow-impedance (second) state. The conducting elements 115, 116, 117, asa response on the radiation, impinging on them, have characteristicimpedance, which cancels in combination with an impedances of thecorresponding connecting elements 119, 120, 121 when are in theirlow-conducting states. In this case the mentioned conducting elements115, 116, 117, being connected by means of the connecting elements 119,120, 121, In this case said set of conducting and connected elementsbecomes conductive for linear polarized radiation in said first spatialdirection and preferably reflects incident radiation being preferablylinear polarized in said first spatial direction When said connectingelements 119, 120, 121 are switched into their second impedance statethe characteristic impedance of the conducting elements 115, 116, 117,as a response on the impinging radiation in a combination with thesecond conducting state of the corresponding conducting elements 119,120, 121, remains high one, and such a quasi-optical switch (IQORS)remains non-conducting and transparent (passing the radiation) for theimpinging said radiation.

Since the conducting elements is connected between each other in one(the first) direction, a biasing and/or modulating signal may be appliedto all said connecting elements via extreme points of the structure(124,125) FIG. 19 which are connected to correspondent extreme points ofeach independent regularly arranged subsets of conductive (115, 116,117) and connecting (119, 120, 121) elements in a configuration of IQORScell illustrated in FIG. 19 via the corresponding independent electricalconnections (122, 123) of FIG. 19 may be fed only to two points (124,125) in FIG. 20 of such a structure (IQORS) via the correspondingcontacts 126, 127 in order to provide with a simultaneous biasing to allconnecting elements of the IQORS and as a result effective modulation ofincident radiation.

If said substrate is transparent for used MMW/SMMW radiation, IQORSfunctions as a transmitting switch, contrary IQORS operates as aradiation-reflecting. For making it opposite side of substrate have tobe cover with metal and thickness of the substrate have to be optimized.

Upon the optical shift of the diodes, which are simultaneouslyilluminated by means of beam of corresponding modulating light signal,problems of electrical inter-connections between a control unit and eachof IQORS do not arise (owing to an absence of necessity of suchconnections).

If the mentioned conducting elements are not electrically connectedbetween each other in the second spatial direction, being preferablyorthogonal to the mentioned first direction, then suach a IQORS cell isquit wide-band (FIG. 20) otherwise IQORS cell 129 becomes frequencyselective enough (FIG. 21) for incident radiation.

The inter-connections in an IQORS 130 may be optimized, as it was shownin FIG. 22. In this case biasing signals are fed from a control unit viaconducting connections 131, 132 immediately to each non-linear element119, 120, but not by means of sequential biasing of the variousconnecting elements 119, 120 via the conducting elements 115,116,117, .. .

The non-linear connecting elements may have the expressed capacitivecharacter (for example, a varactor Schottky's diode), in this case acorresponding selection of impedance of the conducting elements as aresponse on the impinging radiation allows to realize a phase modulationof reflected or passed radiation (see FIG. 24). In order to increase anumber of discrete phase shifts of the dispersed radiation suchstructure may be spatially combined into a set of such IQORS 134, 135,forming a spatial IGOR 133, a space is filled by means of dielectricsubstrata 136, 137 with an optical thickness minimizing a dispersion ofradiation, passing between layers. In this case the diffuser 111 maycomprise namely such volume elements as the independent elements112,113.

Finally, non-linear elements IQORS (diodes) may modulatedquasi-optically (see FIG. 23), when currents, induced at the conductingelements of IQORS of modulated radiation, are preferably distributedalong the conducting elements of mentioned type in one direction, whilecurrents of the radiation are modulated in the other direction 138,139along corresponding conducting elements 140, 141, provided withstructures 142, 143, which are of high impedance for the consideredcurrents and which prevent a mutual influence of modulating currents andmodulated currents.

A principle of modulation of such diffusers for encoding and/ordestruction of spatial coherence is the same one as for the mentionedantenna diffuser.

Sizes of conducting elements of IQORS are selected, taking intoconsideration a condition of an effective radiation modulation, besidestransverse elements of IQSR itself (112, 113 in accordance with FIG. 19)should be sufficiently small in order angular sizes at which the presentIQORS is visible from a spatial point, matched with one of any of theobserved object 9 points (see FIG. 1), in comparison with angular sizesof the diffuser 7 itself (pos. 11 of FIG. 19) as a whole from the samepoint of the illuminated object 9 position. It is understood that inorder to increase sizes of IQORS (112,113 in accordance with FIG. 19),being a part of the diffuser, it is necessary to increase the sizes ofthe diffuser 11 itself and to move it from the observed zone of theobject 9. On the other hand, the sizes of IQORS should be sufficientlysmall ones in order to provide with a necessary diffraction divergenceof beam, modulated by it, for uniform illumination of observation scene.

In order the IQORS functions for any type of polarization it may beprovided with an additional polarization grid, conducting strip of whichare preferably directed to into the second direction, which isorthogonal with respect to the mentioned first direction

In FIG. 25 there is shown an array of the IQORS 111, consisting ofsub-arrays of IQSR (pos. 114 and 115), which are spatially inserted ineach other, are mutually added each other and in each of whichcorresponding separate IQORSs (pos. 146) are oriented by the same way inone direction for one sub-array (144) and in another direction (147) foranother sub-array (145), besides, the mentioned directions are mutuallyorthogonal ones. Besides, the elements in each of the sub-arrays aremodulated in such a manner that side bands of modulation signals foreach of the sub-array are frequency separated. Thus, if on the array alinearly polarized radiation impinges, the direction of polarization ofwhich does not coincide with the mentioned directions, the array will becreate an encoded radiation, consisting of spectral lines, being as partof the doublet, a polarization components of which are orthogonallypolarized.

In FIG. 26 there is shown a principle of amplitude modulation by meansof elements 112. 113 of the array IQORS 111 in accordance with FIG. 19spatially coherent radiation 148 (the previously considered antennaarray functions analogously, but with smaller effectiveness). It is seenthat various portions of regular wave front, impinging at various IQORSs112, 113 (the IQORSs operate with a reflection), are subjected to adifferent amplitude modulation by various way owing to a different intime reflection of the portions of this wave front by various IQORSs.149, 150, 151 are inicatrixes of the dispersion by the correspondingIQORSs 112, 113 in observed instant time. It establishes distinctlymodulated divergent beams of radiation, partitioning an initialradiation with a regular wave front into a corresponding quantity ofindependent components, which equals to a quantity of IQORSs in thearray-diffuser 11, which are a part of such a diffuser.

Thus, the independent portions of the diffuser additionally disperse theindependent spatial components of radiation, which have various anglesof their impinging at a surface of invisible object, and, besides, theyare independently encoded. The radiation encoding by amplitudemodulating IQORSs may be based on the fact, consisting in thatdispersing properties of the diffuser elements are modulated by variousfrequencies, therefore a spectrum of these components will be varied byvarious way, but namely: the spectrum of each separate spatial componentof radiation will consist of at least spectral component on the carrierfrequency of illuminating radiation and additionally at least of twospectral side components, arising in consequence of the mentionedmodulation, which are shifted with respect to main zero components by avalue of modulation frequency. These shifts for the side spectralcomponents render various ones for various elements of the diffuser andthe corresponding radiation components. The diffuser is worked out insuch a manner that an intensity of the mentioned components of radiationafter their reflection by means of this diffuser has been renderedequally by value in all the area of inspection (i.e., it is fulfilled acondition of uniform illumination of the object by a radiation of thementioned component). Therefore any their relative variations after thereflection from the object and hits in the corresponding elements ofreceiving device show on the presence of the differences in theirreflection by various portions of observed objects. Each of separatespatial component of radiation has itself angle of distribution in thearea of the observation. Here each spectral component is a component ofradiation, decomposed in accordance with the angle of the distribution,such a component illuminates the object out of the correspondingdiffuser point and a position of this point in a space is strictlyassociated with a value of frequency of modulating signal for apoint-like dispersing element of diffuser. Regions of localization inthe spectrum of such components and regions of spatial localization ofthe corresponding elements of diffuser, which are responsive ones for ageneration of these components are uniquely imaged an are associatedwith each other, and it is important upon the spectral analysis ofreceived signals and upon their effective decoding. Any relativevariations in amplitudes of the mentioned radiation components, whichare dispersed by each separate point of surface (and/or by inner point)of the object will be strictly determined by means of dispersingcharacteristics of this object in this point. Some of such componentsmay be mirror-imaged from this point (owing to a mirror reflection at adetermined angles of impinging, so called clint effect) and represent bythemselves very strong signals at an output of the receiving arrayelement. In the offered imaging systems such destructing signals will besimply removed or extracted at the step of processing of signals, sincethey have various frequency localizations. A possibility of selectiveextraction of the destructive signals without any influence on the otherinformational signals of image (even only for one pixel of such animage) is a basic property of this modern MMW/SMMW imaging systems,which creates a novel realities for procedures of imaging.

In FIG. 27 there is represented a principle of phase modulation of wavefront 148 by means of array of the IQORS, each of which independentlymodulates a reflected radiation phase. In this case various portions ofreflected wave fronts 152 are subjected to various phase delays in thecorresponding IQORSs 112, 113, and it destructs a spatial synchronism ofthe initial wave fronts 148, impinging onto the diffuser, an creates aspatially non-coherent dispersed radiation 152.

The same effect may be attained in any phase antenna array (PAA) ofpassing 153 (see FIG. 28) or of reflecting type 154 (see FIG. 29),intensively and multilateral worked out at the present time for radarswith controlled beam in the ranges up to the short MM range. (A set ofquasi-optical switches, if phases of radiation, omitted by them, areinterconnected, may be related to the radars with the controlled beam ofscanning).

For the PAA, functioning in the mode of the diffuser, phase shifters155, 156 forming independent elements of the PAA 157, 158 should realizeincidental and independent modulation of the phase of beams, reradiatedby such elements, and it leads resultantly to the incidental modulationof the phase along the wave front of the reflected radiation, and as aconsequence to a destruction of its spatial coherence.

It should be noted, that such diffusers, which are nor capable to encodevarious spatial components of the dispersed radiation, but in wholewhich destruct the spatial coherence of such a radiation, may providewith a high quality of obtained images.

However, it should be noted, that the usage of such diffusers by analogywith optical systems of imaging, in which the spatial coherence of beamof the coherent, as a rule, laser radiation, was destructed, forexample, by means of rotating incidental phase screen, and spatiallynon-coherent images, formed by the optical system by this way possessedof high quality. In contrast to an optical super-short wave radiation,for which a majority of objects are diffusively reflected (except forplainly mirror surfaces) in the millimeter range the above-mentionedapproach does not give a desired improvement, since all the objectspractically reflect its radiation by means of mirror method. In thiscase it is necessary to isolate a mirror component, which completelyturns out in a lens pupil, from a total sum of components, turned out inthe pupil only partially by virtue of sharp directivity of dispersionindicartix and therefore causing signals in a receiving element, whichare significantly less with respect to amplitude. It is necessaryartificially to compare the amplitude of the mirror component toamplitudes of the rest components, realizing a diffuseness of reflectionan creating an image of high quality.

In case of diffusers, which are capable only to destruct the spatialcoherence of the radiation, impinging on them, it may be made only bymeans of illumination of its various spatial portions by various beamsof differently modulated radiation. This situation is shown in FIG. 30,wherein a spatially distributed coherence 159 of the diffuser 7 isilluminated by means of various beams, besides, various beams 160, 161,162, being differently modulated, illuminate various portions of thediffuser. Besides, the reflected radiation 8 of the various beams (witha partially reduced spatial coherence) will impinge onto the surface ofthe object 9 (see FIG. 1) at various angles, and it allows to localize abeam, causing the mirror reflection, independently decoding anddecreasing a level of corresponding signals, received by the receivingdevice RD 16. It is clearly that a quantity of such is more, aselectivity to the mirror reflection of the offered diagram is higher.

Realizations of diffusers, which are capable only to destruct thespatial coherence of the radiation, dispersing by tem, may besufficiently simple ones.

It may be diffusers 163, 164 (correspondingly in FIGS. 31 and 32),consisting of, for example, a set of mirror reflecting small elements165, 166 or 167, 168, a position of which with respect to a generalplane base 169 (or a base in the form of complex surface) is variedrandomly in time, but by a value, that is no more than a half of lengthof intensifying radiation. (Elements, for example, may be connected tomovable magnetic cores of inductive circuit coils 170 (or they may beconnected to crystal-elements 171), fed by accidental electric currents,applied by means of electrical connections 172 from outer electroniccircuits.

The diffuser may consist of independent crystalline liquid (CL) cells,optical (dispersing/passsing) properties of which vary independently bymeans of modulated or accidental modulation signals.

It may be a (spatially distributed) set of resonantly dispersing antenna(narrow-band) systems with slightly different central frequencies,besides, the diffuser is illuminated by means of radiation, scanned withrespect to a frequency and so on.

A possibility of using an imaging system in a wide range of frequenciesof intensifying radiation suggests a possibility of realization of anaccidental screen, having similar technical characteristics in thisrange of frequencies. This, such a screen should be broad-band one andit supposes the presence of a possibility of its using for any harmonicsof the MM range. Let us consider one of these realizations.

It is well-known, that a rotating accidental screen represents a goodrealization of such a diffuser (taking into consideration all the abovesaid). Such a screen represents by itself a reflective metallic surfacewith a regular (in principle of any shape) bedding (mediate) surface andwith accidental deviations of quasi-points of the surface (which mayhave a broad-band realization of dispersion function) from the mentionedbedding surface (a spatial distribution of the points of which withrespect to a depth represents a realization of a random process).Drawbacks of such a diffuser consist in the necessity to rotate a bulkyscreen of large sizes, but its dispersing characteristics are differentand are not predicable ones for a radiation of various frequencies. Itmay be realized a certain modernization of such a screen, allowing toresolve the mentioned problems. In particular, the general diffuser 7may be composed of a set of accidental diffusers 173, 174, 175 (see FIG.33) with relatively small sizes, each of which is rotated around theirown axes and each of which should be separately illuminated by means oftheir own radiation beam 160,161,162, radiated by means of separatesource 179, 180, 181 of distinctly modulated radiation (there are may beradiation elements 2, 3, 4 in accordance with FIG. 14). In FIG. 34 it isrepresented a possible block diagram of imaging with a compositediffuser, consisting of independent accidental diffusers of relativelysmall sizes, which are capable only to destruct a spatial coherence ofimpinging radiation and each of which has e separate oscillator ofMMW/SMMW radiation. The mentioned diffusers 173, 174, 175 of smallersizes are geometrically positioned relative to each other according to aradius of great sphere (182 in FIG. 34) and may composite any othersurface, in a reflective center of which it is located an area 183 ofobservation, in which the observed objects 9 should be positioned inaccordance with FIG. 1. The observation area 183 coincides with a fieldof view of a imaging system 184, in which as a minimum there are thelens 14 and the receiving device 16. The present geometry of theobservation diffuser 182 of the system for imaging and activeillumination 185 is intended for a provision with a maximal range ofimpinging angles of radiation components into the area of theobservation and for a better illumination of the observed objects uponsmaller sizes of diffuser system, and it may practically provide withthe observation area backlighting with 180 degrees, and it completelycorresponds to a character of natural backlighting, but with preferencesof synthesized (encoded) images. In general case the accidentaldiffusers 173, 174, 175 (see FIG. 34) of final small sizes, which areseparately illuminated 179, 180, 181 (see FIG. 34) and forming anilluminated surface 182 of optimal shape, may have any embodiment in asystem for imaging and for active illumination (the PAA, the set ofIQORs and so on, including the above-described rotating diffusers withan accidental reflective surface 173,174, 175, as well as the diffusers,encoding a radiation).

It is understood that the shape of the composite diffuser 182 and evenmore arbitrary shape may be formed also by diffusers, which do notdestruct the spatial coherence, but only diffusively disperse a light.They may be also used in a diagram of illumination of their variousportions by means of various and distinctly encoded beams. However, inthe last case a quantity of possibilities to synthesize improved imagesis less than in case of encoding diffusers or diffusers, which arecapable only to destruct the spatial coherence.

The most broad possibilities to synthesize improved images are opened bymeans of using diffusers, encoding a radiation, dispersed by them.

For an illustration of the above-mentioned and for a furthersubstantiation of the offered method for imaging in FIG. 35 it isrepresented a general diagram for forming of images, masked on the humanbody 186 of dangerous objects (weapon) 9 upon an illumination of theobservation area by means of the radiation 8, dispersed by means of theindependent elements 10, 11, 12, by the of the diffuser 7, encoding thedispersed radiation. A mechanism of functioning of such a diffuser 7 maybe base on the independent amplitude modulation of various portions ofimpinging regular front by different way by various the dispersingelements 10, 11, 12, (for example, it may be an array of amplitudemodulating IQORSs, which is described in accordance with FIGS. 19, 20,26, operates with a transmission (or reflection depending on a diagramof diffuser backlighting by the independent and distinctly encodedsources 3,4 of radiation of fixed or scanned frequency) or any otherencoding diffuser).

Thus, the encoding diffuser 7, in general case, consists of theindependent elements 10, 11, 12, dispersing an impinging on themco-phased wave front of spatially-coherent radiation by independentlyfrom each other way, creating by this way additional partial componentsof radiation, which are independent on each other by phase, besides suchcomponents are encoded by distinctly from each other way and thereforethey may be independently received and decoded in each receiving element47, 48 of the receiving array 46, forming the receiving device 16 (seeFIG. 1). The diffuser 7 is illuminated by the sources 3, 4 ofillumination, a spectrum of which may consist of a set of spectrallydifferent components in a broad range of carrier frequencies, or it maybe continuously scanned in the mentioned range. On the way ofpropagation of the radiation 6 of the sources 3, 4 to the diffuser 7 itmay be located the polarization grid 21 (see FIG. 1), which are notschematically shown in FIG. 35 and separates a linear-polarizedradiation. The radiation of the sources 4, 5 is dispersed and encoded bymeans of the diffuser 7 is directed into the observation region andafter its secondary dispersion by the object 9, as well as by a wear andskin of the carrier-object 9 of individual 186 from the region of theobservation partially turns out into the entrance pupil of the lens 14of the imaging system. (A size of the entrance pupil in most casescoincides with a diameter of the used focusing element (the lens 14)).The focusing element (FE) 14 (for example, lens or mirror) focuses aradiation, dispersed in the region of the observation, into the regionof receiving, in which there is positioned the multi-element array 46.Before the receiving array it may be located the polarization grid 20for separating co- and cross-polarized-components in a radiation,focused by the lens at the receiving array. Besides, the focusingelement 14 establishes a mutually univalent correspondence betweenpoints in the receiving array region and the points of the observationregion corresponding to them, upon which any radiation, dispersed by anydefined point 187 of the object 9 is preferably focused in a determinedpoint of receiving and is received by the corresponding receivingelement 47 of the array 46. Therefore any partial radiation componentsof the diffuser elements 10, 11, 12, which are reflected from the point187 of the object 9 and are hit into the entrance pupil of the focusingelement 14, may be received by the element 47 of the receiving array andare independently decoded by means of electronic block diagrams, forminga part of amplifying and decoding channel of the receiving device 16(see FIG. 1), associated with this receiving element.

In ideal case each point in the region of receiving (in a plane of acuteimage) should be correspond to the determined point in the region ofobservation (in a plane of the object). However, by virtue of finalaperture of the used FE to each point (or the defined region) in thereceiving region the defined region of the observation uniquelycorresponds, and a radiation from this observation region is focused inthis point. In essence, the question is in a volume of acute image forthe considered element of the receiving array, which is obtained uponthe presence of the used FE and a position of which is determined suchthat there is an optical mating of the region/plane of receiving and theobservation region/plane by means of the FE. Lateral sizes of thisvolume are determined by a radius of resolution, resolved by means ofquasi-optical system of resolution element, but a longitudinal size iscorrespondingly determined by means of sharpness depth of the focusingelement (lens). The mentioned final sizes of the resolved elementdetermine spatial sizes of speckle noises and are proportional to sizesof Gibb's oscillations, which are characteristic to the MM images andintensively destruct their quality.

As it was shown, in the MMW/SMMW ranges a reflection of radiation fromthe observation objects is realized mainly by mirror way. The lastmoment determines a low level of quality images, formed in the MMW/SMMWrange, though any methods for a destruction of spatial coherence in afield of view of an imaging system, realized by analogy with an opticalsystems.

Said facts will be clarified by example of evolution of state of phasordiagrams upon a distribution of radiation in a layer of space betweenthe dispersing object and the entrance pupil of the focusing element ofphase diagram of radiation, dispersed by a portion of the observedobject 9 in the point 187 and received by the corresponding element ofthe receiving array 47 (see FIG. 35).

In FIG. 36 there are represented phasor diagrams of radiation in thepoint 187 of radiation in accordance with FIG. 35 nearly with respect toa surface of the object 9 immediately before its dispersion 188 as wellas in the point 47 in accordance with FIG. 35 in case of mirror 189 anddiffusive 190 reflection of radiation by the corresponding portion 187of the object 9 in accordance with FIG. 35, but in FIG. 37 there isshown a block diagram of an imaging system, illustrating a mechanism offorming strong “mirror” and weak “diffusive” components in the signal,received by the element 47 of the array 46 in accordance with FIG. 35.Each phasor (see reference numbers 191, 192) in FIG. 36 corresponds tothe component of radiation, dispersed by the corresponding independentelement 11, 12 of the diffuser 7 in accordance with FIG. 35. Suchphasors practically have the same amplitude (length) and differentmutual phases (193, 194) (the letters are inessential ones, since adiagram of processing isolates squares of lengths of phasors) before adispersed object. If the components are diffusively by means of surfaceportion, the indicatrixes of their scattering have broad angulardistributions 196, 197 (see FIG. 37), which practically overlap by eachother in a space of their propagation. Since a relative portion of wavefronts, corresponding to the mentioned components, dispersed by thisportion, practically will be intercepted by the entrance pupil of thelens 14. Lengths of the phasors of the corresponding components 197, 198(see FIG. 36) after their focusing at the corresponding receivingelement 47 (see FIG. 35) will be practically the same ones (in case ofthe presence of speckles it means that there are equal amplitudes ofspeckle oscillations in the given pints the nearest points for partialcomponents, corresponding to the considered components) therefore thesystem will be operate as a system with ideally destructed spatialcoherence of illuminating radiation and radiation, receiving by thereceiving device with a formation of spatially-non-coherent images ofimproved quality (on account of effect of statistical averaging ofcoherent speckles and a spatial noises of other form). If the componentsare mirror dispersed by means of surface portion, the correspondingindicatrixes of their diffusion have narrow angular distributions 199,200 Therefore the relative portion of the wave fronts of thecorresponding components will be intercepted by different way by theentrance pupil of the lens, since a mirror surface of the scatteringindicatrixe 201 hits in the entrance pupil of FE 14 only for a part ofthe elements 11 of the diffuser 7, while for the rest elements 10 it isintercepted only diffusive (relative small) portion 202 by the FE 14.

Therefore in the phasor diagram 189 a phasor responsible forspecular-reflected radiation component 203 dominates in comparison witha phasor of any diffusive-reflected radiation component 204.

If the radiation components are not modulated, a signal, received by areceiver, can be detected only as an inseparable sum of squares of thecorrespondent phasors. Since in this sum only the signals dominate,which are formed only by a limited part of the closely-positioned pointscatterer 11 an image, formed by them, will be again spatially coherentand will exhibit speckle noises, which are inherent for such images,despite the object is illuminated by radiation being spatiallyincoherent in the object region. Since each of considered component ofradiation both in the object region and in the receiving region exhibitshigh spatial coherence (because it is formed by point-like portion ofthe diffuser, the angle of observation of the diffuser portion from anypoint of the object region should be practically delta-shaped),therefore an image, formed by such a component, will be spatiallycoherent and will have a noise speckle distribution, which is inherentto it. Thus, when a illuminated radiation is reflected by observableobject by specular manner (that it is inherent for the MMW/SMMWradiation) traditional destruction of the radiation coherence in theobject region (in contrast to an optical range) will not allow toimprove a quality of formed image and to make this image free fromcoherent speckles and from influence of the Gibb's effect.

If the partial radiation components are modulated, there existspossibility to vary their relative contribution to every pixel of theresultant image by means of both hardware and software because each ofthem can be distinctly received by receiver. In this case there appearspossibility to artificially convert a bad-quality specular image tohigh-quality diffuse-like image. (it is schematically shown by the arrow205 in FIG. 36).

Let us analyze possibilities of the above-mentioned correction ofcontributions of partial radiation components for values of pixels ofresultant images in case of the usage of the radiation-encodingdiffuser.

In accordance with a principle of superposition a complex amplitude ofradiation in a point of receiving (for example, in input of receivingantenna) may be presented as a sum of complex amplitudes (phasors) ofpartial radiation components. Each of said component was primarilyscattered by one of a particular cell (or in other words a spatialportion) of the diffuser and then, after of its propagation towards theobservation area the component was secondary scattered by the portion ofthe observed object surface, which is optically conjugated withaforesaid point of receiving (m,k) due to radiation focusing, and inprocess of further propagation the component partially hits intoentrance pupil of the imaging system.

-   -   (1)

It is understood that the sum is performed over all the independent cellof the diffuser (index I is a maximal number of the diffuser cells alonga diffuser cell row, J is a maximal number of the diffuser cells alongdiffuser cell columns respectively). For a simplicity of considerationthe independent cells of the diffuser 7 are arranged in the form oftwo-dimensional rectangle array, wherein each element has its ordernumber in array row i and array column j. It allows to uniquelydetermine a spatial position of every diffuser cell including itsposition relatively to every points of illuminated object 9 being underobservation. In this case the order numbers of the diffuser celluniquely determine angles b_(i,j) of incidence of cell-created partialradiation components on any portion of the observed object surface.φ_(i,j) ^(m,k)({right arrow over (x)} _(m,k),β_(i,j))=φ_(i,j)^(sc)+φ_(i,j) ^(pr)({right arrow over (x)} _(m,k),β_(i,j))+φ_(i,j)^(ob)({right arrow over (x)} _(m,k),β_(i,j))  (2)

In the formula φ_(i,j) ^(sc) is a phase value of the considered partialradiation component immediately after its scattering by the diffusercell (i,j); φ_(i,j) ^(pr)({right arrow over (x)}_(m,k),β_(i,j)) isaverage change of the phase value of the radiation component after itspropagation from said diffuser cell to the receiving point (since thisterm does not vary in time and does not influence on the final result,it will be omitted in further formulae), at last φ_(i,j) ^(ob)({rightarrow over (x)}_(m,k),β_(i,j)) is an additional phase random changearising due to additional propagation of the radiation components fromreal position of scattering portion of the scattering object surface upto focusing lens object plane along correspondent additional propagationpath being equal d_(d) (arising the term is responsible for propagationof the radiation component in followings of the scattering surface), andat last.^(α) ^(t) ^(d) {circumflex over (V)}_(i,j) ^(m,k)—is a complex amplitude(phasor) of the part of said partial radiation component, which wasreflected by said portion of the object surface, then hits into theentrance pupil of the imaging system and then was focused in the pointof the receiving plane y_(m,k). The amplitude of the focused radiationis determined by said part of the radiation component, which hits intothe entrance pupil of the focusing lens and depends on scatteringindicatrix of the portion of the object surface for the radiationcomponent, which is quasi-optically matched with the correspondent inputof receiving antenna by means of the focusing lens (the aforesaidscattering indicatrix is mainly determined by type of radiationscattering which can be both specular or diffusive). In general case forsaid phase change it may be written that $\begin{matrix}{{\phi_{i,j}^{ob}\left( {{\overset{->}{x}}_{m,k},\beta_{i,j}^{m,k}} \right)} = {2\pi\quad\frac{d_{d}\left( {\overset{->}{x}}_{m,\quad k} \right)}{\lambda_{l}}\frac{1}{\cos\quad\beta_{i,j}^{m,k}}}} & (3)\end{matrix}$wherein d_(d) is a distance (or an optical distance if the object ispositioned in a medium) from the scattering portion of the surface (206)of the object to the focusing lens object plane (207) (in other words,the input plane of the focusing lens which is optically matched with thereceiving plane of the focusing lens in accordance with formula for athin focusing lens) (see FIG. 38); β^(m,k) _(i,j) is an angle (208) ofincidence of partial radiation component being scattered by diffusercell (i,j) on the portion of the object surface at space point x_(m,k),;α_(t) ^(d)—is a symbol, characterizing some physical feature ofradiation used for illumination of the diffuser, for which index mark tcan show a type of distinctive physical feature of the radiationcomponent (for example, index mark t can indicate a carrying frequencyof radiation component some limiting region of the diffuser, illuminatedby the radiation source (t can indicate consideration of both saidfeatures together for correspondent said symbol and so on); besidesindex mark d can indicate a concrete value of the correspondent feature(for example, some order number of t can indicate the value 94 GHz forthe carrier frequency or indicate the portion the illuminated diffusercells (5, 25; 20,45), which is disposed within the diffuser cells (5,25; 20, 45), located between diffuser columns (5, 25) and the diffuserrows (20, 45): d can indicate even a combined set of such values in acase if the index t characterizes set of radiation features ofradiation-illuminated radiation).

Voltage at an output of averaging non-linear detector (in assumptionthat all the harmonics of carrier frequency are filtered) for signalreceived at the considered receiving point y_(m,k) may be written as$\begin{matrix}{{{{}_{}^{\alpha td}{}_{m,k}^{}}\left( {\overset{\leftarrow}{y}}_{m,k} \right)} = {{\sum\limits_{i,{j = 1}}^{I,J}\left\langle \left( {{}_{}^{\alpha td}\left. V \right.\hat{}_{i,j}^{m,k}} \right)^{2} \right\rangle_{T}} + {2 \cdot {\sum\limits_{l,{n = 1}}^{I,J}{\sum\limits_{i,{j = 1}}^{I,J}{{{{}_{}^{\alpha td}\left. V \right.\hat{}_{i,j}^{m,k}} \cdot {{}_{}^{\alpha td}\left. V \right.\hat{}_{l,n}^{m,k}}}\left\langle {\cos\left\lbrack {i\left( {\phi_{i,j}^{m,k} - \phi_{l,n}^{m,k}} \right)} \right\rbrack} \right\rangle_{T}}}}}}} & (4)\end{matrix}$where T is a characteristic time of the signal averaging by theaveraging circuits of said detector. In case, when a relative differenceof phase values for the radiation components, being scattered bydifferent diffuser portions, does not vary in time (this is valid incase when the diffuser does not capable to change spatial coherence ofdiffuser-scattered radiation), then the signal at the output of saiddetector will consist of both terms of the formula (4) and, thus, willinclude interference additives, which will depend on the phasedifferences between the radiation components. In this case variouspartial images with essentially distinct speckle content may be formedonly due to changes of values of radiation physical features which arecharacterized by the symbol α_(l) ^(d) (the radiation features are notassociated with a spatial coherence of the radiation or, in other words,with various directions of incidence of partial radiation components onthe surface of the object). In this case quality of the resultant imagemay be enhanced (for example, it is valid when only radiation carrierfrequency is changed, moreover, in this case the image enhancement willbe achieved even if the illumination radiation is directed towards theobject. However, in this case, the requirements to the range of thecarrier frequency variation will be more high than in case of the usageof the additional scattering diffuser).

For eliminating the second interference term in aforesaid formula saiddifferences of the phases should be varied in time. This casecorresponds to case of formation of spatially incoherent images, Thecase takes place, when during said time duration T the difference of thephases for different radiation components of the signal is essentiallychanged at least within range 2p (6,28) radian.

Namely it may be realized due to special designing of the dynamicaldiffuser in which there are realized the phase changes φ_(i,j) ^(m,k),which are varied in time and different for different cells (i,j) of thediffuser (the changes may be both accidentally varied in time orregularly).

In another realization of the imaging system including the diffuser, theindependent components may be created due to distinct modulation ofilluminating radiation in every cell (l,j) of the diffuser andcorrespondingly distinctly received (for revealing both the absolutevalue of phasors of the received components and squares of the values).

In both cases the second term of sum in aforesaid formula, describingeffects of mutual interference of the partial radiation componentsformed by different cells of the diffuser is suppressed (in this caseinter-modulation term in the detected signal becames equal to zero)while the first term of the sum becomes to be proportional to timeduration of exposure T (it is supposed that all the modulations of thesignal are removed by previous demodulation circuits). Thus the signalat the averaging non-linear detector output is equal to $\begin{matrix}{{{{}_{}^{\alpha td}{}_{m,k}^{}}\left( {\overset{\leftarrow}{y}}_{m,k} \right)} = {\sum\limits_{i,{j = 1}}^{I,J}\left( {{}_{}^{\alpha td}\left. V \right.\hat{}_{i,j}^{m,k}} \right)^{2}}} & (5)\end{matrix}$

Thus, the recorded signal is a sum of squares of modules of amplitudesof received partial components (the sum of squares of lengths of thecorrespondent phasors (see FIG. 36)) and is proportional to sum ofpowers of these components (every term of the sum is proportional to apower of correspondent radiation components), accumulated during thetime T, at that any interference term is negligible.

In essence the formula (5) means that the signal at the output of saidaveraging non-linear detector is a sum of the averaged powers (in otherwords spectral densities of radiation exhibiting some set of physicalfeatures which were accumulated during an interval of the imageexposition) of partial images formed by partial phase-independentradiation components (in accordance with the formula (5)) each of whichwas scattered by one of the independent scattering element of thediffuser by accident manner.

When the diffuser-illuminating radiation is scattered by aforesaiddistinctive manner, then at every receiving point the different partialradiation components may be received distinctly from each other, atthat, received signal may be considered as a set of correspondentconstituent (or in other words partial) signals (as separable set ofsuch signals) and characteristics of said constituent signals (forexample, their power) may be distinctly determined.

-   -   (6)

Such set of the signals allows to rearrange the formula (5) to theformula in which every sum term, being responsible for particularconstituent signal, is additionally multiplied by arbitrarily-chosenweight coefficient (thus the set is characterized only by a value).

-   -   (7)

Matrix image obtained by aforesaid manner is an array of independentelements (in other words pixels every of which is characterized by saidvalue) every of which will be visualized (being complementarilyspatially arranged) in the form of a resultant entire image.

-   -   (8)

Besides, weight coefficients will be chosen under requirements of anobtainment of the resultant image exhibiting the best visual qualityand/or information content. Since said coefficients may be varied by anarbitrary way (when the signals are converted in digital form and loadedin memory they can be multiply processed by a digital processor), anumber of such sums is really great, the same is valid for a number ofvariations of relative contribution of each constituent signal in atotal value of correspondent pixel (being equal to the aforesaidweighted sum) of the resultant (entire) image. It allows, in particular,to reduce one of the constituent signals which can correspond to aparticular partial radiation component being specularly reflected fromparticular portion of object surface and which is redundantly largerelative to other constituent signals corresponding todiffusely-reflected partial radiation components. Such similartransformation of a pixel value may be performed for any other pixel ofthe resultant image may be with different weighted coefficients, atthat, a number of terms summed for formation of the pixel value is equalto a number of constituent signals extracted form a compound signalbeing received by correspondent receiver and further decoded. Suchweighted summation which nay be different for different portions ofresultant image is important because conditions for enhancement by saidsynthesis procedure may be different for different portion of theresultant image.

In general case the object is illuminated by radiation which isscattered by a diffuser additionally performing secondary encoding ofthe scattering radiation, at that the encoding is different for variousspatial portions of the diffuser. The radiation, that is directedtowards the radiation-scattering diffuser may consists of severalphysically distinctive radiation components which are primarily encoded(such a double encoding of every radiation components being scattered bythe diffuser allow to distinguish ones from each other, such additionaldoubly-encoded radiation components appears due to scattering theprimarily encoded radiation components by the diffuser which, in turn,creates multiple additional radiation components, being encoded for thesecond time, from every said primarily encoded radiation component).

-   -   (9)        From aforesaid set of multi-parametric data a lot of different        resultant (entire) images may be obtained due to post-imaging        processing including weighted summation synthesis of every pixel        of the resultant image. The resultant images will exhibit        different specific radiation features (from monochromatic        spatially-incoherent images to polychromatic spatially-coherent        images and, at last, to polychromatic spatially-incoherent        images. The later takes place when the object is illuminated by        the “the white” radiation).    -   (10)

The aforesaid weighted summation synthesis approach is valid for such acase when it is used a traditional diffuser being able to destroyspatial coherence of radiation but without its encoding _([L2])different spatial portions of which are illuminated with differentradiation beams being distinctly encoded. As this takes place, theradiation beams can exhibit all the same radiation physical featuresexcept the spatial localization of spatial portions of the diffuserilluminated by them, besides a particular radiation beam illuminates abeam-associated diffuser spatial portion. In this case the compoundsignal of every receiver consist of a set of independent constituentsignals

-   -   (11)

every of which exhibits power being equal to an inseparable sum ofpowers of signals every of which is responsible for the radiationcomponents which are scattered by those non-encoding diffuser cellsbeing disposed within a diffuser portion illuminated by one of saidradiation beam. In this case said cells form a distinctive group of thecells which is marked as (I^(c), J^(c)), where c is an index mark of thegroup. If the group has rectangle form it includes the cells within cellmatrix (I^(c) _(min), J^(c) _(min); I^(c) _(max), J^(c) _(max)). If thegroup has other spatial form the aforesaid power summation also has tobe performed over all diffuser cells included into the group.

-   -   (12)

A value of every pixel of the resultant (entire) image is determinedfrom criteria of optimization of the resultant image therewith saidvalue is the result of synthesis of correspondent constituent signals(being equal to a weighted summation of time-averaged powers of thesignals)

-   -   (13)

therewith the weighing coefficients are determined by aforesaidoptimization criteria. Said coefficients being associated with the sameradiation parameter α_(t) ^(d) but with different cells groups(I_(c),J_(c)) may be different for different pixels (m,k) of theresultant combined image.

The coefficient may be the same for different pixels so it means thatthe whole constituent partial image comprising the whole image pixelmatrix (M,K), which exhibits radiation physical features α_(t) ^(d) and(I_(c),J_(c)), will be formed to be added wholly in resultant image. Thecoefficient may be the same only for portions of the whole image pixelmatrix (the matrix is determined by whole set of samples performed bythe receiving means in receiving plane of imaging system). The size ofthe portions may be different and may consist of any amount of pixels upto one pixel only. At last if it is used _([L3]) the diffuser all cellsof which distinctly encode scattering radiation then aforesaid techniqueof grouping the diffuser cells may be realized by digital manner inmemory of a computer. In this case every term of the power summationwithin a particular group can have own weighing coefficient (it allowsto eliminate disturbing signals (for example, onesbeing responsible for specularly reflected radiation components) alreadywithin the cluster $\begin{matrix}{{{{}_{}^{\alpha td}{}_{m,k}^{I^{c},J^{c}}}\left( {\overset{\leftarrow}{y}}_{m,k} \right)} = {\overset{I_{\max}^{c}}{\sum\limits_{I_{\min}^{c}}}{\overset{J_{\max}^{c}}{\sum\limits_{J_{\min}^{c}}}{\left( {{}_{}^{\alpha td}{}_{i,j}^{m,k}} \right) \cdot \left( {{}_{}^{\alpha td}\left. V \right.\hat{}_{i,j}^{m,k}} \right)^{2}}}}} & (14)\end{matrix}$

This case may be reduced to the previous one, by supposing that theweighting coefficients for terms corresponding the signals belonging thesame cluster are equal to each other ^(α) ^(t) ^(d) R_(i,j)^(m,k)=const.

The aforesaid technique of clustering allows to form resultant imagesexhibiting different conditions of object illumination with differentcharacteristic points of illumination and different characteristicspatial sizes of correspondent spatially-incoherent source(correspondingly it may be changed as well a radiation temporalcoherence, its polarization, etc.). Such processing may be performed byprocessing means in real time after procedure of image informationacquiring by hardware part of imaging system therewith a lot ofpeculiarities will be revealed by means of visualization of observableobject and following analysis (including computer one) of said images.This is possible even without a usage of encoding diffuser or without ausage of any diffuser at all (in this case object-illuminated radiationcomponents have to be encoded) but a number of possible resultant imagesand capabilities of said analysis will be reduced.

If cells of the diffuser are electronically controlled and there existsability to vary modulation parameters of cell-controlling signals thenre-arranging of said clusters may be made by hardware as well.

As it takes place the modulation parameters (for example, frequencies ofshifting of side band components of the radiation which appear afteramplitude modulation of radiation by the diffuser cells) may be madealmost the same for cells within the same cluster the latter makespossible clustering of the modulation parameters. Such approach allowsto jointly select correspondent constituent signals responsible for thesame cluster which are encoded by almost the same manner therewith finaldecoding circuits of receiver may detect only summing power of thecorrespondent compound signal (which is the result of summing oftime-averaged powers of constituent signals from the cluster). In thiscase there is no necessity to extract a constituent signal from saidcompound signal.

For example, in case of the mentioned amplitude modulation eachfrequency cluster may be isolated by means of frequency selectivecircuit, detected in order to separate an envelope and then accumulatedby any low-frequency filtering circuit.

At last, it is necessary to find parameters, which are suitable for ageneral estimation (or even for a complete analysis) of characteristicsof any partial constituent image. Such a partial constituent image(characterized by a two-dimensional matrix image with a number ofpixels, either corresponding to a number of receiving elements in a caseof usage of receiving starring array or to a number of spatial samplingpositions of the receiving elements in case of a usage of mechanicalscanning of such elements _([L4]) for whole sampling of the image, inthe last case 3D sampling of receiving area is possible as well) may beformed by filling every pixel of its image matrix by only suchconstituent pixel value (for example ^(α) ^(t) ^(d) S_(m,k) ^(I) ^(c)^(,J) ^(c) ) from a correspondent whole set of constituent pixel valueswhich is responsible for a constituent signal being characterized bychosen particular set of encoding indexes α_(t) ^(d),(I_(c),J_(c)) (inother words, by radiation physical features α_(t) ^(d)(I_(c),J_(c)) etcof the correspondent constituent radiation component associated withsuch a signal). Such an image may be presented in the form of a set,^(α) ^(t) ^(d) S^(part) (in other words, in the form of two-dimensionalpixel matrix with dimensions (M,K)) of pixels, values of which areresponsible only for those constituent signals which exhibit the samechosen particular set of encoded indexes α_(t) ^(d),(I_(c),J_(c)) etc_([L5]). $\begin{matrix}{{{}_{}^{\alpha td}{}_{}^{}} = {\overset{M,K}{\bigcup\limits_{m,{k = 1}}}{{}_{}^{\alpha td}{}_{m,k}^{I_{c},J_{c}}}}} & (15)\end{matrix}$

Since various partial images will exhibit different levels of theiraverage powers, it may be introduced a parameter, characterizing theimage average power level. It _([L6]) may be a value (due to the factthat pixel values are non-negative) $\begin{matrix}{{{}_{}^{\alpha td}{S\_}_{}^{I^{c},J^{c}}} = \frac{\sum\limits_{m,{k = 1}}^{M,K}{{{}_{}^{\alpha td}{}_{m,k}^{I^{c},J^{c}}}\left( {\overset{\leftarrow}{y}}_{m,k} \right)}}{M \cdot K}} & (16)\end{matrix}$

This parameter shows an average level of image power over all pixels ofcorrespondent constituent image. Certainly, such a parameter may beintroduced, if it is necessary, for any portion (limited number ofpixels) of each constituent image.

It should be noted that, as to the technique of formation of resultantimages _([L7]), correspondent partial constituent images and constituentpixel values may be obtained by means of different realizations ofhardware. For example, it may be used a starring non-scanningtwo-dimensional array of receivers or a single mechanically-scannedreceiver, radiation physical features of illumination radiation may bescanned in time (for example, carrier frequency of illuminationradiation beam may be scanned or the beam may be mechanically scannedalong different portions of a diffuser, etc.), then correspondentconstituent signals will be obtained in various time moments aftercorrespondent changes of values of said radiation features (properties),moreover an observable object may be illuminated by several partialradiation components simultaneously then the components have to beencoded and the receiver should have corresponded decoding units fordistinctive receiving of these components.

At last it is _([L8]) possible a case, when the values of radiationphysical features of several constituent radiation components ofcomposed radiation are scanned in time simultaneously and, besides thecomposed radiation may include components all physical features of whichare non-varied in time, in any case correspondent hardware may have (andshould have) such a realization which will allow to extract all encodedsignals in all sequential time moments of changing/keeping constant oftheir radiation features values.

Generally for a technique of synthesizing of said resultant imagesconcrete realizations of system hardware may be different. However,system hardware realizations, allowing to obtain the greatest amount ofsaid constituent signals in the shortest time intervals, and in idealcase, simultanously, are pereferrable.

An inherent impossibility to obtain object images with high quality inthe MMW/SMMW spectral range in cases, when spatially coherence ofobject-illuminatiung radiation is traditionally destroyed in area ofobject localization, is caused by that the resultant signal of receiveris an unseparable sum of multipl_([L9])e terms. In this case every suchterm is not so individually, as complementary informatively importantfor forming a quality image as a whole. However, in the MMW/SMMW rangein such sum only one term or very limited number of ones dominate (whichare responsible for specular reflected radiation components) which arenot sufficiently representative components to be used for forming aqualitative image.

Since the aforesaid sum presents a summation of powers (intensities) ofsaid partial radiation components (in receiving area such components areequivalent to corresponded partial image), it is expedient to encodedifferent radiation components. Said encoding approach will allow toseparately determine power values of said different encoded signals,after their receiving and decoding in every sampling spatial pointwithin receiving area, and then electronically change their relativecontributions for evere pixel of the image for enhacing image quality.

In this case there exists possibility to synthesis high quality“diffuse” images even when observable object specurlarly reflectsilluminating radiation.

In order to realize the proposed approach it _([L10][L11]) is necessarythat each independent cell 10, 11 of diffuser 7 (see FIG. 35) preferablyperforms distinctive regular phase, frequency or amplitude modulation ofcell-scattered radiation rather than _([L12]) aforesaid non-distinctiverandom modulation of one. In this case because primary partialconstituent radiation components, which were generated by correspondentradiation sources 3,4,5, are initially modulated then their seconddistinctive modulation by different portions of the diffuser allows todefinitively identify correspondent constituent signals, including thosesignals being responsible for different scattering diffuser portions, inany receivers associated with correspondent receiving input elements47,48 of correspondent receiving input array of receiving unit 16 whichincorporates correspondent signal-decoding circuits.

As this takes place, the first initial demodulation allows to identify aspecific radiation source (and correspondent specific features of thediffuser-illuminating radiation such as carrier frequency, polarization,beam-illuminated diffuser portion), the second modulation allows topoint at the _([L13]) specific cell of the diffuser) or diffuserportion) which has scattered the radiation of said source towardsilluminating object. In contrast to optics MMW/SMMW apparatus allows touse effective radio-engineering methods for practical realizations ofaforesaid operations.

In FIG. 39 it is presented a diffuser array 7 (which can have one ofaforesaid realizations, for example, it may be the array IQORS 111showed in FIG. 19) providing independent amplitude modulation ofincident radiation with every diffuser independent cell. Electronicallycontrolled cells 10,11 of the diffuser array 7 in FIG. 1 (equivalently,cells 112, 113 of the diffuser array 111 in FIG. 19). transform incidentspatially coherent radiation into scattered radiation with destructedspatial coherence (therewith, the scattered radiation is decomposed intomultiple constituent radiation components being modulated distinctlyfrom each other. _([L14])

Independent cells of any aforesaid encoding diffusers, after theirillumination by spatially coherent radiation exhibiting regular wavefront, additionally create independent spatial constituent radiationcomponents due to amplitude modulation of the scattered componentsexhibiting different angles of its incidence on surface of an objectdisposed within observable area, therewith said radiation components areindependently encoded. The distinct encoding in the case is based on thefact, that scattering properties of the diffuser cells are modulated bymodulation signals exhibiting different frequencies, therefore aspectrum of created partial constituent radiation components, scatteredwith different cells of the diffuser, will be definitely changed. Butnamely: due to aforesaid amplitude modulation a spectrum composition ofevery said constituent spatial radiation component will consist offundamental (zero) spectral component with frequency equal to a carrierfrequency of diffuser-illuminating radiation and, additionally, a twoside-band components appearing due to said modulation which are shiftedrelatively to said fundamental component by value being equal to aparticular frequency of one of said modulation signal Ω^(mod). Thefrequency shifts of said side-band components are different for theradiation scattering by different diffuser cells. The diffuser isdeveloped by such way that intensity of every of radiation componentsbeing scattered with the diffuser appears to be the same for differentdirections within the observable area (that is, the observable area isuniformly illuminated by every of aforesaid radiation components). InFIG. 39 there is schematically represented the consideredamplitude-modulating diffuser, which is in essence an array of theabove-considered modulation structures (for example, the IQORS), each ofwhich has its own frequency of AM modulation Ω^(mod) of the scatteringradiation.

In FIG. 40 it is presented a spectrum 209 of one (positive) band of theside-band components of the resultant (reflected from all the set ofdiffuser cells) radiation at a particular spatial point in theobservation area. This spectrum consists of practically uniformly-filledset of spectral lines (210, 211,) of said partial radiation components,every of which may be received by the same receiving input element (m,k)and value of every of which corresponds to a power value of that_([L15] [L16]) determined separate (decoded) partial constituentradiation component (averaged during exposure time interval) which wasscattered towards the observable object with a correspondent cell (l,j)of the diffuser array. Besides, it is supposed that the diffuser arraywas illuminated by means of radiation, characterized by the determineddistinctive physical features or a set of these features a^(t) _(l) (asit was considered above), wherein indexes marks indicate thecorrespondent physical feature and features set or even set of thefeatures, for example the feature may be radiation carrier frequency at94 GHz. A number of the independent spectral components is equal to atotal number of cells in the diffuser array (I×J) therewith J is anumber of cell rows in the diffuser array, J is a number of cell columnsof one. The values of the spectral components are preferably almost thesame at points within the observable area before interaction ofcorrespondent radiation components with the object due to design of thediffuser.

Any relative changes of the constituent radiation components (seeFIG. 1) after their reflections from the object 9 and, finally, aftertheir collections with the correspondent receiver input elements 47,48,. . . of the receiving unit 16 demonstrate differences in saidreflections from different portions of observable object 9. Every suchspectrally-distinctive constituent radiation component exhibits specificangle direction(ch) of its propagation in observable area. Every suchcomponent is a component of diffuser-scattered radiation which isdecomposed into constituent radiation components every of which exhibitsdistinct angle directivity of its propagation due to the fact that everysuch object-illuminating component is originated from correspondentdiffuser spatial point. Position of every such spectral radiationcomponent in the aforesaid component spectral distribution is definitelyassociated with spatial localization of a correspondent diffuser cellwhich is responsible for creation of such _([L17]) radiation componentand this fact is essential for providing an analysis of correspondentsignals in obtained image signature. In FIG. 41 it is shown a detailedstructure 212 of spectral distribution of a signal, including spectrallines 210, 212, which are received with one 47 of the receiving inputelements of the receiving array 46 after reflection of radiation fromthe object and after its focusing on the receiving input element (in aarray representation of the receiving array this element has a position(1,4), i.e., it is positioned in the row 1 and in the column 4 of thereceiving array).

For illustration goal in FIG. 41 it is shown a dominated “specularlyreflected” spectral component 210, associated with the cell 10 of thediffuser (in a array representation of the diffuser-array this cell hasa position (3,3), i.e., it is positioned in the row 3 and in the column3 of the diffuser) and a weak “diffusively reflected” spectral component211, associated wit the element 11 (in the array representation of thediffuser-array this cell has a position (20,2)).

For more clear graphical illustration of peculiarities of the spectrallines distribution of the decoded signal (210) (which are spectrumpresentation of the signal, received by only one receiving input element47 of the receiving array 46) a two-dimensional diagram-arrayrepresentation of the distribution is introduced. Structural arrangementof the diagram-array is similar to structural arrangement of thediffuser cell array the cells of which are responsible for correspondentradiation spectral components. The spectrum 212 (see FIG. 41) of saidsignal of the receiving input element 47 (or (1,4) element in aforesaidarray notation) is transformed into an matrix-diagram 213 in such amanner that each spectral line component _([L18]) 210, 211 of thespectrum 212 fills such an matrix element position in the matrix-diagram213, which is occupied by that cell of the diffuser array 7, which hascreated said spectral line (the cell creates the spectral line componentby distinctly encoded scattering of this component) Thus, appearance ofthe matrix-diagram 213 allows to exactly estimate a contribution ofvarious cells of the diffuser in a formation of content of signalreceived by aforesaid receiving input element associated with the imagepixel indexes (1, 4)._([L19])

Analogous matrixes-diagrams will be produced for any of the receivinginput elements of the receiving array. Thus a multi-parametermulti-dimensional image signature _([L20]), received with the M-by-Nreceiving array in a case when the object 9 is illuminated by a singleradiation component, being scattered by the I-by-J encoding diffuserarray, is a set of M-by-N pixel groups _([L21]) every of which is aI-by-J matrix of pixel values. When a sizes of the receiving array andthe matrix-diagram are large then there can be received a great volumeof information being equal to multiplication M×M×I×J×Y where Y is anumber of bytes in digital representation of value of correspondentconstituent signal power in computer memory.

In essence, said matrix-diagram is an arranged set of power values ofconstituent signals containing in the signal received with correspondentreceiving array element (m,k) (it may be such a signal which wasreceived by a receiving element in a particular sampling spatial pointwhen the receiving element is mechanically scanned within an imageplane) wherein said constituent signals are originated withcorrespondent cells of I-by-J diffuser array being illuminated withradiation beam exhibiting a particular set of physical features.Therewith after changing a value of, at least, one of physical featuresfrom said physical features set a new matrix-diagram is generated whichcorresponds to the new value of the physical features (or new values ofthe set of the features). This situation is illustrated in FIG. 45.

Every of receiving elements of the receiving array (and a receivingdevice) (and correspondingly said pixel group of a multi-parametricmulti-dimensional image) receives (contains) information volume whichcan be presented in the form of a particular set (like set 214) ofaforesaid matrixes-diagrams (like 216,217,218, . . . or 219,220,221, . .. which characterized by a specific value of some radiation feature (orby specific values of the radiation features from said set of radiationfeatures) of diffuser-illuminating radiation.

Besides, it is clear that each of different said sets of thematrixes-diagrams will contain one matrix-diagram characterized by oneof changeable said values of said radiation features (or, at least, oneof changeable said values of said set of said features) ofdiffuser-illuminating radiation (this takes place because the encodedradiation components are received by all the receiving elements of thereceiving array). This is essential that the diffuser may besimultaneously illuminated with distinctly encoded radiation componentsexhibiting different values of said radiation features or values of saidradiation features are scanned or some combination of the cases takesplace. It is important that object would not essentially change itsforeshortening relative to input pupil of the focusing lens.

A partial constituent image may be formed by means of filling everypixel of the image by a power value of the correspondent constituentsignal from correspondent set of matrixes-diagrams, like set 214associated with said pixel, for example, pixel 47 in FIG. 45 (formedfrom signals correspondingly received with the receiving element beingassociated with said pixel), therewith all said power values are ones ofthose constituent signals which exhibit the same values of radiationfeatures of a correspondent object-illuminating constituent radiationcomponent (such a specific value of carrier frequency, polarizationstate, and diffuser cell indexes indicating a directivity of thecell-originated radiation component). Partially or fully synthesized(really combined) image may be formed by means of filling every imagepixel by a weighted sum of several power values of correspondentconstituent signals from such a matrix-diagram set which is associatedwith the pixel therewith a number of said constituent power values andsets of values of radiation features of the object-illuminatingradiation components responsible for the values are the same fordifferent pixels of such images (

—

).

Depending on aforesaid choice of said specific constituent power valuessuch images may exhibit different averaged radiation features ofimage-formed radiation. It may be monochromatic spatially-coherentimages, monochromatic spatially-incoherent images, or, for example,polychromatic spatially-coherent images, or, at last, “white” image withradiation exhibiting determined angle of incidence on object surface andetc. (the choice may be performed in accordance with formalism discussedearlier with connections with formulas (5)-(16)). Every such image mayreveal additional distinctive information on observable object (forexample different distinctive specific peculiarities of object surfacemay be revealed by illuminating the object by radiation componentsexhibiting different carrier frequencies or different angles of itsincidence on object surface).

Besides, such images may be also obtained by usage of only hardware partof the imaging system, when a formation of aforesaid sums of powervalues of constituent signals in every pixel-receiver (as it wasdiscussed including in connection formulae (5)-(16)) is realized byunits of receiving apparatus.

Combining of the formed partial constitution images (by either hardwareor software manner) and forming their summation synthesized image withelimination (or only with a decrease of their large contributions in thesummation image) of disturbing partial constitution images with a highlevel of noises (or reducing of the contributions of their portionswhich may consist of any number of image pixels down to one pixel) isthe most simple but effective processing

Any relative changes in amplitudes of the constituent radiationcomponents after their scattering with different points of surface(and/or internal points) of object will be strictly determined byscattering properties of the object in these points for every values ofradiation features from correspondent set of the features. Some of suchradiation components may be reflected specularly by some said points ofthe object (so called “glint” effect, the specular reflection atdetermined angles of radiation incidence) and produce very strongconstituent signals at output of correspondent element of receivinginput array. By analyzing the spectrum of aforesaid constituent signalsthe constituent signals responsible to specularly-reflected radiationcomponents may be easily determined because they are originated withdiffuser cells modulated with correspondent modulation signalfrequencies.

In the simplest variant of the aforesaid technique such destructingconstituent signals may be simply eliminated or extracted at a stage ofprocessing of the signals. An ability of selective extraction of thedestructing constituent signals (

) without any influence on other informational signals of image (evenonly for one pixel of such an image) is a basic property of said novelMMW/SMMW imaging system, which makes available novel imagingpossibilities.

In FIGS. 42 and 44 it is shown a spectral distribution of power ofradiation encoded signals received by the considered receiving element47 (associated with a correspondent multi-parameter image pixel) ofreceiving array after extraction of disturbing constituent signals(including signal 210), being responsible for specularly-reflectedradiation components, from the correspondent composite signal, therewithsuch an extraction procedure may be performed by processor 56 (see FIG.10). A variation of values of spectral components are inherently causedwith speckle structure of correspondent partial constituent images,however, averaged deviations of such values relative some their averagevalue are shown to be the same and it provides a high quality of aresultant image after correspondent usage of such spectral lines for thesynthesis of the image.

If, besides, such a diffuser is illuminated with various beams ofradiation exhibiting different physical values of radiation features(the beams, besides, are differently encoded) or if these values areadditionally scanned in time (or only some part of them) theninformation on object, which can be received by the imaging system,greatly increases. Therewith partial volumes of the information whichbecomes available for calculating values of correspondent pixels,similar to pixels 47, 48, of resultant images (which can be described inaccordance with formula (9)) can be presented in the form ofcorrespondent matrixes-diagrams sets, similar to sets, 214, 215. Suchvolumes of information allows to use more comprehensive possibilitiesfor analysis of parameters of an observable object and its surface andmore comprehensive possibilities of forming high-quality resultantimages of any type and physical nature (spatially-incoherent images,quasi-monochromatic spatial coherent ones, “white” ones, etc.).

Therewith there may be revealed unique pecularities of the objects,which are inaccessible from analysis of traditional images. For example,a large volume of the information allows to reveal structural parametersof the object surface from the analysis of partial constituent coherentimages. Particularly it is known that speckle distributions of theimages are changed while changing values of physical features ofobject-illuminating radiation. Therewith these changes are different indifferent pixels of the images depending on values of deviation of thesurface in correspondent spatial points from averaged form of thesurface. By means of analysis of dependences of such changes versusposition of point-like cell of a diffuser and wavelength of illuminatingradiation it may be revealed an inclination angle of surface (or thevalue of the deviation) of the surface at correspondent point and evenorientation of the inclination in a case of a large scale inclination.Using such a multi-parameter statistical information on object a reliefof the object surface or even object internal structure (when objectmaterial is transparent for MMW radiation, for example, in case ofceramic weapon) may be determined.

It is understood that a number of possible procedures of the optimalanalysis processing and further synthesis processing of resultant imagesis greatly increased with a growth of the information volume, which maybe obtained on the base of the proposed imaging method.

To show a capabilities of the proposed method for synthesizing highquality images there were obtained some results of digital simulation ofprocedure for forming a resultant image and enhancement of its qualityby means of minimization of influence of disturbing partial constituentimage in the process of summation of different of partial constituentimages to synthesize their resultant image. For the simulation partialconstituent images are chosen taking into account their probableappearance, however, procedures of their complete or partial summationare processed exactly by means of computer simulation.

Seven partial constituent images from 222 to 228 (see FIG. 46) may beexperimentally formed, for example, in such realization of illuminationsubsystem which is based on usage of a traditional diffuser beingcapable only to destroy spatial coherence of scattered radiation withoutany additional encoding of the radiation. Therewith spatially-distinctportions of the diffuser are illuminated with distinctly-encodedindependent radiation beams by such way that every of said diffuserspatial portions is illuminated only by one of said illumination beams(see FIGS. 30,33-34). In such case every said radiation beam forms itsown partial constituent image, like 222,223, (such image ischaracterized with particular averaged angle of incidence ofilluminating radiation on observable object), therewith all said imagesmay be simultaneously received with receiving apparatus 16 due to theirdistinct encoding. From another side, said partial constituent imagesmay be obtained by means of mechanical scanning of a singlerelatively-narrow radiation beam over said diffuser and, as result,sequential formation of correspondent partial constituent images 222,223.

In aforesaid cases every partial constituent image may be described withformulae (12) and possible resultant images may be described withformula (13) in the latter weighted coefficients may be different fordifferent constituent component of the resultant compound image (13) forevery its pixel.

Noise-like partial constituent images 222 and 228 may be naturallygenerated as a result of illumination of object 9 at particular anglesof radiation incidence when correspondent illumination beams arespecularly reflected from individual clothes 229 of said object 9 or dueto other reasons (see FIG. 47).

An averaged matrixes-diagram 230 (obtained as a result of of averagingof aforesaid matrixes-diagrams over all pixel values of correspondentpartial constituent images for illustration differences in middleenergies of correspondent partial constituent images 222-228. Therewithvalue of the element with indexes (1,1) of the average matrix-diagram231 is equal to averaged energy of the image 222, value of the elementwith indexes (3,2) of the average matrix-diagram 232 is equal toaveraged energy of the image 228.

In the FIG. 34 it is shown a classical resultant image 233 which will bereceived with usual radiometric imaging system which, traditionally,does not include any aforesaid signal-decoding units. Said image willhave such appearance even in case when the observable object 9 will beilluminated with aforesaid radiation when the radiation is formed due toscattering of said distinct radiation beams with diffuser beingprimarily illuminated with the beams by aforesaid manner (moreover, suchimage will be characterized with low quality in any cases ofillumination of the diffuser). The resultant image 233, if it is used aformalism of the formula (13) for its description, is obtained in acase, when weighted coefficients associated with pixels of summedpartial constituent images are the same for any pixels of any saidpartial constituent images are the same (or, in other words, it isobtained by means of direct non-weighted summation of all the partialconstituent images 222 to 228, including also the disturbing images 222and 228). In this case a noise in the images 222 and 228 is additivelyadded to the object information content in partial constituent images223 to 227 (the latter images may be also distorted for other reasons (apartial spatial coherence caused limit sizes of correspondent radiationbeam), however if only such images are summed without said disturbingimages then their summation can generate good quality resultant combinedimage).

Aforesaid technique of image formation is a classical technique whichcan be based on usage of any of known methods of radiometric approach inpassive imaging or on usage of active imaging approach which is based onsimple destruction of object-illuminating destruction.

Thus, anyone radiometric imaging system may receive and visualize onlyone-parameter images of image 233 type, which will always exhibit lowquality in situations when the object 9 is carefully concealed.

On the other hand, proposed imaging system forms multi-parameter imageof 234 type in the form of set-stack of partial constituent images, eachof which is characterized by own values of physical features ofradiation forming such an image.

A simple extraction of three images 222, 227, 228 (see FIG. 48) of theseven images leads to formation the set-stack 235, only consisting ofthe lesser noisy images 223, 224, 225, 226, the summation of whichresults in the resultant image 236 exhibiting enhanced quality andinformational content. Correspondent averaged matrix-diagram 237 isshown in FIG. 48 which illustrates above mentioned average powercontributions in the new resultant image 236, and the matrix-diagram hasno contributions associated with the disturbing images.

Results of mathematical simulation of above-mentioned procedure ofsummation of contents of the selective images in correspondent imagepixels are shown in FIG. 48. Therewith, weighting coefficients weretaken the same for different pixels belonging to the same partialconstituent image but different for different for pixels belonging todifferent images 222 to 228.

In FIG. 49 there are illustrated possibilities of conventionalmathematical post-imaging processing of the initial conventional image(the passive image 233) and the synthesized resultant image 236.

Pairs of images 238, 239; 240, 241; 242, 243 are pairs of such imageswhich are generated as a result of conventional mathematicalpost-imaging processing of correspondent aforesaid images 233, 236,therewith the processed images in every said pair are subjected to thesame type of the processing procedure (spatial low-frequency filtration,contour enhancement, etc). It is easy to see that such processingprocedures become more effective, if the noisy image 233 is substituteby its new appearance 236 according to aforesaid method oftransformation of said contributions in pixel values of the finalresultant image 236 (on the based of aforesaid synthesis method), thanapplications of conventional methods of processing becomes moreeffective 239,240,243 in comparison with the cases of their applications238,240, 242 to original noisy image 233.

In FIG. 50 there are presented various variants of electronic groupingof cells 10,11, 12 of the diffuser 7 in clusters. In the first casewhich is illustrated in the left part of FIG. 50 diffuser cells isgrouped in clusters of rectangle shape 244, 245, 246. It takes place dueto varying of values of encoding parameters for said cell-encodingsignals. In encoding unit such values are generated to be matched withcorrespondent bands of 247,248,249 of such parameters (the bands arecharacterized with correspondent bandwidths and central values of theencoding parameter) in correspondent decoding unit. In the second case,being illustrated in the right part of the FIG. 50, diffuser cells aregrouping in clusters of concentric circle forms 250,251,252 therewithsaid encoding signals for which are fitted in the correspondent saidresolution bands 247,248,249 of encoding parameter of correspondentdecoding unit. In the first case correspondent partial constituentimages will be characterized with different angles of incidence ofcorrespondent partially-coherent radiation, Second case will allow todistinctly reveal parts of observable object having sphere shapes byanalyzing correspondent partial (or in other word, constituent) images.Aforesaid clustering may be realized in real time for radiationcomponents exhibiting different frequencies or frequency bands ordifferent polarization states.

Aforesaid approach in encoding of partial (or in other words,constituent) radiation components may be realized by means of differentmethods.

The above-described approach in encoding of radiation components may berealized by means of various methods and approaches.

A main problem of active imaging systems consists in the requirement ofextremely possible decreasing of level of radiation 132, lighting theobservation region (see FIG. 34). This aim, in particular, may beattained by means of the usage of two and more narrow-band oscillatorsof MMW/SMMW radiation, frequencies of which are shifted relative to eachother, and their difference frequencies are synchronically phased bymeans of high-stabilized oscillators of difference frequencies. In thiscase, though an unstability of frequency radiation of the oscillationsthemselves, their difference signals, obtained in the receiving device,will be characterized by super-high frequency stability and by anarrowness of band, which are practically identical with respect thesame characteristics of signals of the difference frequencies of thementioned oscillators.

The mentioned difference signals, obtained in anyone receiving channelof the receiving device RD 16 by means of feeding a sum of all saidsignals, are received by antenna of the receiving element 47 and aredetected at a quadric diode (in case, when it is used a doublet(multiplet) realization of partial radiation, illuminating the object ordiffuser, or in a mixer, when one of such signal is additionally fed toa heterodyne input of the mixer, which is a part of the mentionedreceiving channel, but the rest signals are fed to a signal input ofthis mixer).

A phase stabilization of the difference frequency of spectrally shiftedcarriers for two or several such signals allows to solve this problem ofhigh sensitivity of receiving equipment as well as to realize aneffective encoding of partial radiations.

The first problem may be solved by means of maximally possibleconcentration of signal energy, carrying an information about the objectreflecting surface properties in an extremely narrow band of thedifference signal, separated individually in a receiving portion ofsystem for each element. It takes a place though the fact that anintrinsic stability of free-running oscillators in MMW/SMMW ranges isnot good and it does not allow in principle to attain the requiredstabilization of frequency and correspondingly such a spectralconcentration. Besides, a super-high energy concentration of thedifference signal is attained for frequencies, in a region of which thespectral power of excessive noises of electronic component (but thereare the frequencies at least no less than of 10 to 15 MGz, but it iscompletely attainable that they may be over 3 GHz and so on depending onthe realization of doublet line oscillator) becomes minimal one and ischaracterized by only the spectral power of heat noises, which althoughare not practically eliminable for none spectral range, but in thementioned range of the difference frequencies are characterized bynegligible small value (for the band of frequencies of 1 GHz it ischaracterized by the value of 10⁻²⁰ W).

Thus, a approach, consisting in the extremely possible narrowing of thedifference signal of paired components of doublet sigbal (or, it isequivalent one, of a spectral concentration of energy of a signal,reflected by the object) and its partial stabilization (up to 1 Hz ofthe difference signal deviation), an on the other hand, a transfer ofits frequency in the range with an extremely low level of inherentnoises of the electronic equipment (niises I quite low at frequency 1GHz and gigher) allows to attain an extremely high sensitivity ofreceiving equipment of the imaging system (but it means that there isattainable a super-low level of active radiation, lighting human wear,that is significantly less in, but, on the other hand, it allows toattain an increased dynamic range of the spectral concentration of thereceiving equipment.

The latter is important one in connection with a mirror reflectionradiation of this range from observed objects, and it determines a greatdynamic range of signals, reflected at arbitrary angles from theobserved object surface an at angles of the mirror reflection. Besides,it is obvious that if the dynamic range of the receiving equipment isinsufficient one, only radiation components, mirror reflected from theobject, will be visually reflected, and it automatically determines anextremely low quality of formed images.

In accordance with the present invention a transceiver of imaging systemfor an obtainment of complete information about a radiation, dispersedby the object, under conditions of low level of the object illuminationpower in accordance with the first example of embodiment comprises aheterodyne receiver, intended for a receiving MMW/SMMW radiation ofimages of said imaging system, a source of MMW/SMMW radiation, intendedfor an illumination of the object or diffuser, which disperses thesource radiation into the direction of the object, besides, theheterodyne receiver includes a receiving antenna, connected to a firstsub-harmonic mixer for a receiving a signal at its reference input, afirst radiation oscillator, fulfilling a function of the heterodyne forsaid mixer, a first band filter, connected to the first mixer for aseparation of intermediate frequency signal, a second sub-harmonicmixer, a signal input of which is electrically connected to an output ofthe first band filter, but a reference input is intended for a receivingof reference signal, multiplied with respect to a frequency by a firstmultiplier of the oscillator signal frequency, a second band filter, aninput of which is connected to an output of the second mixer, ahigh-frequency or low-frequency analyzer of signal, an input of which isconnected to an output of the second mixer, means for signal samplingand processing, connected to an output of the analyzer, a source ofradiation represents by itself a second radiation oscillator, an outputof which is connected to an input of a second frequency multiplier, anoutput of which is connected to a radiation antenna and includes acontrol unit for controlling of radiation frequency of the secondradiation oscillator by means of frequency of the first radiationoscillator by means of forming a signal of difference frequency of saidoscillators and by means of providing with a phase synchronization ofsaid difference signal by the signal of the first oscillator ofreference signal by means of regulating of the second oscillatorfrequency, the oscillator of the reference signal is intended for anactivating of the control unit and for a generating of the referencesignal for said signal analyzer, but the first and second multipliers ofthe signal source frequency and the first sub-harmonic are designed witha capability of functioning upon a harmonic of the same order.

In this transceiver the signal analyzer represents by itself twoanalogous-digital converter, realizing a synchronous quantization of thesignal from the output of the second band filter andfrequency-multiplied signal of the reference signal oscillator from thefirst frequency multiplier and a processor, having a memory for loadingsample sets of said quantized signals and designed with a capability ofa computation of amplitude and phase information on signals (or onlytheir power), received by the receiving device 16. In this transceiverthe control unit represents by itself a first directional coupler,connected to an output of the first oscillator and realizing a divisionof the first oscillator signal with respect to a power into a smallerand greater portions, a second directional coupler, connected to anoutput of the second oscillator and realizing a division of the firstoscillator signal with respect to a power into a smaller and greaterportions, a mixer, inputs of which are intended for a receiving of thesmaller portions of said first and second oscillators and which realizesa separation of a difference frequency signal out of said signals for afeeding of this difference signal via the band filter into one input ofphase detector, another input of which is intended for a receiving asignal of said reference signal oscillator, but an error signal of thephase detector, which is a signal of phase mismatch between thedifference frequency signal of the signals of said first and secondoscillators and the signal of the reference frequency oscillator, is fedonto a controlling electrode of the second oscillator for a variation ofthe frequency signal of the second oscillator and for a decrease of saidphase mismatch.

The heterodyne receiver of the transceiver may be mounted on amechanically scanning device with a capability to receive of completeimage radiation, formed by a system of imaging by means of theheterodyne receiver scanning in a plane of focused image of this system.

The heterodyne receiver of the transceiver may be designed in the formof an array of heterodyne receivers, disposed in such a manner thatphase centers of said antenna receivers of each heterodyne receiverscoincide with a plane of sharp image of imaging system, but eachheterodyne receiver is provided with a directional coupler for atransmission a portion of the power of the second oscillator onto aheterodyne input of the corresponding first mixer, but said secondoscillator is a general one for all the heterodyne receivers, each ofwhich is designed with a capability to receive a portion of its powervia the corresponding direction coupler.

In accordance with the second embodiment example a transceiver of systemfor imaging of MMW/SMMW images for an obtainment of detail informationabout a radiation, dispersed by the object, under conditions of lowlevel of the object illumination power comprises a receiver for directamplification and detection of MMW/SMMW radiation, intended for areceiving of MMW/SMMW radiation images in said system for imaging, asource of composite MMW/SMMW radiation, intended for an illumination ofthe object or diffuser, which disperses the source radiation into thedirection of the object, besides, the receiver for direct amplificationand detection includes a receiving antenna, connected to an amplifier ofhigh frequency, a signal of which is fed into a square-law detector, ananalyzer of signal, an input of which is connected via a filter to anoutput of said square-law detector, means for signal mapping andprocessing, connected to an output of the analyzer, a source ofcomposite radiation, consisting of a first radiation oscillator,connected to a first directional coupler and dividing the signal of thefirst oscillator with respect to a power onto a greater and smallerportions, and of a second radiation oscillator, connected to a seconddirectional coupler, dividing the signal of the second oscillator withrespect to a power onto a greater and smaller portions, of outputantenna system, intended for a transmission of said greater portions ofpower of signals of the first and second oscillators in a free spacepreferably by the same way, a control unit, onto inputs of which fromthe corresponding outputs of said directional couplers there are fedsaid signals of smaller power of correspondingly first and secondoscillators and which is intended for controlling of radiation frequencyof the second radiation oscillator by means of frequency of the firstradiation oscillator, and an oscillator of reference signal, intendedfor an activating of the control unit and for a generating of thereference signal for said signal analyzer.

The analyzer of signal for this example may represent by itself a bandfilter with a central pass frequency, corresponding to a frequency ofsaid oscillator of reference signal, connected to an analogous-digitalconverter, realizing digital samplings of signal and loading thesesamplings to a memory of digital processing means, realizing aprocessing of these samplings in order to obtain whole set of parameterof a spectral composition of this signals including spectral densitydistribution. Besides, the analyzer may additionally include a mixer, asignal input of which is connected to a an output of said band filter,but onto a reference input of said mixer there is fed a signal of thereference signal oscillator, and an output signal of said mixer via thefilter is fed onto an input of the analogous-digital converter,realizing a digitazing of signals and filling by their samples thememory of the processor, besides the processor realizes a digitalprocessing of these samples in order to obtain a spectral composition ofthis signal.

The control unit for the transceiver in case of this example ofembodiment represents by itself a mixer, inputs of which are intendedfor a receiving of the smaller signal portions of said first and secondoscillators and are connected to the corresponding outputs of said firstand second directional couplers, and which realizes a separation of thedifference frequency signal out of said signals for feeding of thisdifference frequency signal via the band filter onto one input of thephase detector, another input of which is intended for a receiving ofsignal of said reference signal oscillator, but an error signal of thephase detector, which is a signal of phase mismatch between thedifference frequency signal of the signals of said first and secondoscillators and the signal of the back-up frequency oscillator, is fedonto a controlling electrode of the second oscillator for a variation ofthe frequency signal of the second oscillator and for a decrease of saidphase mismatch.

Besides, the receiver for the direct amplification and detection may bemounted on a scanning device with a capability to receive of completeimage radiation, formed by a system of imaging by means of theheterodyne receiver scanning in a plane of sharp image of this system.

In a region of sharp focusing of focusing element it may be positionedan array of said receivers for the direct amplification and detection insuch a manner that antennae of said receivers are positioned near to aplane of sharp image of the focusing element.

In case of the usage of a set of said composite radiation sources, uponwhich frequencies of signals of the reference signal oscillators o ofthe corresponding sources differ from each other, to an output of thesquare-law detector of the receiver for the direct amplification anddetection there are parallel connected several said analyzers ofsignals, a number of which equals to a number of said sources ofcomposite radiation in said set, and a central frequency of the bandfilter of the corresponding analyzer equals to a frequency of signal ofthe reference oscillator of the corresponding source of the compositeradiation.

In case of the usage of the set of said sources of composite radiation,upon which the frequencies of signals of the oscillator of the referencesignals of the corresponding sources differ from each other, to anoutput of the square-law detector of the receiver for the directamplification and detection there are parallel connected several saidanalyzers of signals, a number of which equals to a number of saidsources of composite radiation in said set, and a central frequency ofthe band filter of the corresponding analyzer equals to a frequency ofsignal of the reference oscillator of the corresponding source of thecomposite radiation, besides onto an reference input of mixer of saidsignal analyzer there is fed a signal of reference oscillator of saidsource of the composite radiation.

Besides, various sources of the composite radiation from the set of thesources are intended for an illumination of preferably spatial-differentportions of the object or diffuser. Various sources of the compositeradiation from the set of sources have essentially different theiraverage frequencies, calculate as an arithmetic mean of frequencies ofcorresponding paired oscillators.

A radiation of said greater portion of signal of the first oscillator,distributing in a free space, is preferably linearly polarized in afirst spatial direction, but a radiation of said greater portion ofsignal of the second oscillator, distributing in a free space, ispreferably linearly polarized in a second spatial direction. In thiscase the first spatial direction coincides with the second spatialdirection or the first spatial direction is orthogonal to the secondspatial direction.

The receiver may be provided with a polarization means, separating aradiation, linearly polarized in the first spatial direction, from aradiation, impinging on it, or the receiver may be provided withpolarization means, separating a radiation, linearly polarized in thesecond spatial direction, from a radiation, impinging on it.

The frequencies of the first and second oscillators of the compositeradiation are simultaneously increased or decreased in a sufficientlywide range of frequencies, but said control unit saves said controllingof frequency and phase of the second oscillator by means of a frequencyand phase of the first oscillator in all the mentioned range of thefrequencies.

In accordance with the following embodiment of the invention atransceiver of system for imaging of MMW/SMMW images for an obtainmentof detail information about a radiation, dispersed by the object, underconditions of low level of the object illumination power comprises areceiver for direct amplification and detection of MMW/SMMW radiation,intended for a receiving of MMW/SMMW radiation images in said system forimaging in a plane of its focusing element sharp image, a source ofMMW/SMMW radiation, intended for an illumination of the object, thewhich disperses the source radiation into the direction of the object,the receiver for direct amplification and detection includes a receivingantenna, connected to an amplifier of high frequency, a signal of whichis fed onto a square-law detector, a high-frequency of low-frequencyanalyzer of signal, an input of which is connected via a filter to anoutput of said square-law detector, means for mapping and processing,connected to an output of the signal analyzer, the radiation sourceconsists of a composite radiation source and diffuser, which isilluminated by a radiation of said composite radiation source and whichdisperses to a side of the object a radiation, impinging on thediffuser, said diffuser consists of spatially distributed pointdispersers, realizing a distinctive modulation of radiation, dispersedby them, a source of composite radiation, consisting of a firstradiation oscillator, connected to a first directional coupler anddividing the signal of the first oscillator with respect to a power ontoa greater and smaller portions, and of a second radiation oscillator,connected to a second directional coupler, dividing the signal of thesecond oscillator with respect to a power onto a greater and smallerportions, of output antenna system, intended for a transmission of saidgreater portions of power of signals of the first and second oscillatorsin a free space preferably by the same way, a control unit, onto inputsof which from the corresponding outputs of said directional couplersthere are fed said signals of smaller power of correspondingly first andsecond oscillators and which is intended for controlling of radiationfrequency of the second radiation oscillator by means of frequency ofthe first radiation oscillator, and an oscillator of reference signal,intended for an activating of the control unit and for a generating ofthe reference signal for said signal analyzer.

In this example of the embodiment, said signal analyzer represents byitself a bandpass filter with a central pass frequency, corresponding toa corresponding frequency of said reference signal oscillator, connectedto an analogous-digital converter, realizing digital samplings of signaland fillings by these samplings a memory of processor, realizing aprocessing of these samplings in order to obtain a spectral compositionof this signal said analyzer may additionally consist of mixer, a signalinput of which is connected to an output of said band filter, but to areference input of said mixer there is fed a signal of the referencesignal oscillator, and an output signal of said mixer via the filter isfed to an input of the analogous-digital converter, realizing digitalsamplings of signal and fillings by these samplings the memory of theprocessor, besides the processor realizes a digital processing of thesesamplings in order to obtain a spectral composition of this signal.

For this example the control unit represents by itself a mixer, inputsof which are intended for a receiving of the smaller signal portions ofsaid first and second oscillators and are connected to the correspondingoutputs of said first and second directional couplers, and whichrealizes a separation of the difference frequency signal out of saidsignals for feeding of this difference frequency signal via the bandfilter to one input of the phase detector, another input of which isintended for a receiving of reference signal of said reference signaloscillator, but an error signal of the phase detector, which is a signalof phase mismatch between the difference frequency signal of the signalsof said first and second oscillators and the signal of the referencefrequency oscillator, is fed to a controlling electrode of the secondoscillator for a variation of the frequency signal of the secondoscillator and for a decrease of said phase mismatch.

It may be used a set of said sources of composite radiation, besides thefrequencies of signals of the oscillators of the reference signals ofthe corresponding sources should differ from each other, but to anoutput of the square-law detector of the receiver for the directamplification and detection there are parallel connected several saidanalyzers of signals, a number of which equals to a number of saidsources of composite radiation in said set, and a central frequency ofthe band filter of the corresponding analyzer equals to a frequency ofsignal of the reference oscillator of the corresponding source of thecomposite radiation.

For this example of embodiment it also may be used a set of said sourcesof composite radiation, besides, the frequencies of signals of theoscillator of the reference signals of the corresponding sources differfrom each other, to an output of the square-law detector of the receiverfor the direct amplification and detection there are parallel connectedseveral said analyzers of signals, a number of which equals to a numberof said sources of composite radiation in said set, and a centralfrequency of the band filter of the corresponding analyzer equals to afrequency of signal of the reference oscillator of the correspondingsource of the composite radiation, besides to an reference input ofmixer of said signal analyzer there is fed a signal of referenceoscillator of said source of the composite radiation, and, besides, toan reference (heterodyning) input of mixer of said signal analyzer thereis fed a signal of reference oscillator of said source of the compositeradiation.

The simplest block diagram of a device based of usage of pairedoscillators with a stabilized frequency of frequency difference beatsignal of paired-oscillators signals is presented in FIG. 51 (early inthe text the device was called as the oscillator of doublet spectralline upon a consideration of its functional diagram in connection withFIG. 14. Further such an oscillator will be called either as anoscillator of mutually coherent signals (OMCS) in case of its usage inillumination subsystems of imaging systems or an oscillator of doublet(or multiplet) spectral line (carrier frequencies) in case of its usagein telecommunication systems.

The device (see FIG. 51) consists of two oscillators 59 and 60 ofMMW/SMMW ranges, operating at nearly the same frequency, wherein atleast one oscillator 60 is the VCO (the oscillator, radiation carrierfrequency of which is controlled by means of external voltage signal).In case of waveguide realization of the oscillators at their outputsthere are disposed correspondent isolators 84,85 for preventing backscattering returns to inputs of the oscillators from other parts of thedevice. By means of directional couplers 91 and 92 smaller parts ofpower of signals of the oscillators 59 and 60 via corresponding couplersoutputs are fed to the mixer 93 (nonlinear element) inputs in order togenerate frequency difference beat signal (said couplers is chosen in amanner that one said smaller part is higher in power another smallerpart at least by a factor of ten to provide effective mixing operation),said difference signal from the mixer 93 output is fed to the input ofthe frequency selective circuit 94, consisting of a band filter 253(tuned on a central frequency of the frequency difference beat signal),in series connected to an amplifier 254 (which can be a saturationamplifier to determine value of outpur signals), and from an output ofthe amplifier 254 is fed to one of inputs 96 of a phase detector 95, toanother input 97 of the phase detector 95 there are fed a referencesignal of the reference quartz high-stabilized oscillator 98 or one ofits harmonics which may be formed in a frequency multiplier 255, beingin series connected to said reference quartz-stabilized oscillator 98(this reference oscillator may be thermo-stabilized also, thereforephase noises of such an oscillator are negligible small ones). An errorsignal (correction voltage) from the output of the phase detector 95 isfed to an input of a filter 256 and from its output it is fed to anamplifier 257 of the frequency-selective amplification unit 100 and thenis fed to the control electrode 101 of the VCO 60. Besides, a frequencypassband of the filter 256 is selected by optimal way in order toprovide correct operation of the above-described phase-lock loop (PLL)(with a low level of phase noises and/or filtration of high-frequencycomponents of the difference signal). Upon a correct selection ofbandwidth of both the filters 253 and 256 which finally determines ofcharacteristic time of the PLL, the error signal, formed by the phasedetector 95, adjusts a frequency of the VCO 60 in order to decrease(eliminate) phase differences between said frequency difference signalof two oscillators 59 and 60 and the signal of the reference oscillator98 (or its harmonics if oscillator 98 is fed to frequency multiplier togenerate its harmonics 255). Due to the phase locking, the frequencydifference beat signal produced by the mixer 93 is frequency- and phasetied to the reference signal of the reference oscillator 98 (or couple98, 255).

Greater portions of the signals of the oscillators 59 and 60 fromcorresponding outputs 258 and 259 of the directional couplers 91 and 92than may be radiated in free space (or may be used by another way),after passing through corresponding (amplitude or phase) modulators 62,63, each of which is in series connected to a corresponding transmittingantenna 260 and 261. It may be used both the individual antennae 260,261each of which is associated with correspondent waveguide channels ofpassing the greater portions of the signals of the oscillators 59 and60, in another aspect of the embodiment said waveguide channels may becombined by means of couplers 262, 263 into the common waveguide 86 fortransmitting doublet spectral line radiation via the a single commonantenna 67.

The frequencies of such signals are shifted with respect to each otherby a frequency value of signal of the reference oscillator 98 (orsequence of the reference oscillator 98 and multiplier 255) generatingspectrally pure stable narrow reference signal and their differencesignal is phase-synchronized by the signal of said frequency-stabilizedreference oscillator 98 (or the sequence 98,255). Besides the samedifference signal will be generated in the receiving device from thedevice-generated doublet spectral line after its propagation fromtransmitting antenna (antennas) of the device through observable sceneand imaging system up to a receiving antenna of the receiving device(see FIG. 10). Therewith said generated difference signal will exhibit astable and narrow spectrum similar to one of the signal of thequartz-stabilized reference oscillator 98. The frequencies of signals ofthe oscillators 59 and 60 in a case when both the oscillators arevoltage control oscillators may be simultaneously and synchronouslyvaried in value in some limits (the limits depends of its realization)either for simultaneous frequency increase or simultaneous frequencydecrease, for example, under the control of the scanning unit 90 (seeFIG. 14), besides, owing to the described circuit diagram of thephase-lock loop the difference signal of these oscillators will bephase-locked by the above-mentioned way and will possess theabove-mentioned spectral purity (but signals of separate oscillators,swept in this pair in frequency, will possess of their mutual phasecoherence because the signals are phases-linked to each other). The rateof the frequency sweeping have to be matched with the characteristictime of the used PLL for due operation of the device. A sweepingfrequency range of the swept paired oscillators may be sufficientlylarge (for example in case of usage of BWT or YIG oscillators it mayextend the operation frequency band till several tens of GHz). It allowsto obtain frequency-different partial images acquired in a wide range offrequencies upon a super-low power level of illuminating radiation, soto obtain a principally novel information on observable object in theform of spectrally distinctive images.

Additionally such an device based on paired-oscillators may be also usedfor three-dimensional (volume) imaging by means of usage of aquasi-optical imaging approach, in which the radiation signal of one ofthe swept oscillators 59 is used for an illumination of an observableobject, but the signal of another oscillator 60 is fed to the heterodyneinput of the mixer in a channel of amplification of the receiving device16, the separated difference signal of the output of the mixer will bemutually phase-coherent with respect to the signal of the stabilizedfrequency reference oscillator 98 for phase signal of differencefrequencies, and besides it will comprise a phase information,concerning a distribution of signal of the oscillator 59 till theobject, its reflecting and focusing on a receiving array. The feed ofsaid difference signal from an output of the mixer to a signal input ofsequential synchronous detector and the feed of signal of the differencesignal oscillator 98 to a support input of the synchronous detector (bymeans of coaxial cable) provide with an obtainment of “I” and “Q”channel signals on the output of the synchronous detector, comprising aninformation about an amplitude and a phase of the signal of theoscillator 59, reflected from the object. An obtainment of such signalsfor various carrier frequencies of the oscillator 59 (positionedequidistantly on an axis of the frequencies) and a fulfillment of fastFourier transforms with the obtained file of complex numbers will givean information about a reflection coefficient and depth of dispositionof centers, dispersing a radiation, in accordance with radar techniqueof frequency-synthesized impulse. Besides, it will be the informationabout the reflected radiation, focused only on one of receivingelements, electrically connected to the considered amplification channelof RD 16. Upon a carrying out of the same operations with signals,received by other receiving channels, (the receiving elements 47, 48 ofwhich (as of early considered one) is optically mated with correspondingreflecting portions—points of the object 9) it will be obtained the holeinformation, on the grounds of which it may be constituted a volumeimage of the object, being in a field of view of the focusing element(lens) 14 (see FIG. 1). It should be noted that such three-dimensionalimages (obtained without of diffuser) will suffer from mirrorreflections, however, speckle distortions will be minimized, sincevarious phase of signals, reflected from various portions, distinctlypositioned by depth, will be remitted into the information about thedepth of position, and it make such a system free from speckledistortion along with a capability to form three-dimensional images.

The above-shown block diagram demonstrates functional arrangement of thepaired-oscillators device, realized in a waveguide performance. The samedevice may be designed in the integral performance in the form of fullymonolithic semiconductor device, in this case, in accordance with themonolithic embodiment of oscillator devices, the antennae 260 and 261are parts of the corresponding oscillators 59, 60 and serve both as aplanar antennae for emitting of generated radiation signals in freespace and as a corresponding resonator systems being a part ofcorresponding oscillator (for example properly connected to acorresponding non-linear element with a negative impedance for ageneration of signal, for example, to Gunn's diode or to amplifier withpositive feedback). In this case the modulators 62, 63 may be excludedout of the oscillator (here it may be modulated a difference frequencyof such an oscillators). The directional isolators may be also excluded.The directional couplers 91, 92 in the monolithic embodiment fulfils thesame function of extracting of smaller portions of energies of thesignals, generated by the planar oscillators 59, 60, an of feeding theminto the planar mixer 93. All the other elements, including also thephase detector 95 and frequency-selective amplification units 94, 100may be carried out in accordance with the integral monolithicsemiconductor technology on the same substrate. The oscillator 98 ofreference signal should preferably be external.

Such a paired oscillators device may be quite inexpensive (upon a massproduction) and may find the wide usage in receiving/transmittingtelecommunication MMW/SMMW systems. Besides, on one base it may bedisposed several paired oscillators with various difference frequencyand even with various own frequencies of oscillators (upon a variationof their antennae configuration). Antennae may be various ones forvarious pairs and paired antennae may be differently oriented on onebase (equally for antennae in pair, but differently for various pairs).

In FIG. 51 the phase detector 95 an the frequency-selective amplifyingunit 100 consisting from the amplifier 257 and the filter 256 is groupedin an unit 264 of the phase-lock loop 2 (PLL2), having one output 265,coinciding with (electrically connected to) an output of the amplifier257, and two inputs, an input 266 coinciding with the signal input 96 ofthe phase detector 95, and by an input 267 coinciding with another (forreference signal) input 97 of the phase detector 95, besides, theadditionally mentioned the united unit 264 (PLL2) is united with themixer 93 and the frequency-selective unit (the filter 253 connected inseries with the amplifier 254) into united servocontrolling unit 268(phase-lock loop 1—PLL1), having an output 269, coinciding (electricallyconnected to) with the output 265 of the unit 264, and three inputs, aninput 270 is at the same time the first input of the mixer 93, thesecond input 271 of the unit 268 is the second input of the mixerelement 93, and the third input 272 coincides with the reference input97 of the phase detector 95.

Finally, the unit 268 of the phase-lock loop 1, being united with theoscillators 59,60, the directional isolators 84, 85 and the directionalcouplers 91, 92, forms an oscillator of mutually-coherent (paired)signals (OMCS) 102 or in other words the oscillator 102 of doubletspectral line (doublet carriers). In the last case the mentioned OMCS isspecifically used for radiating both the spectral components in freespace via the common output antenna 67 (see FIG. 51) or by means of twopreferably equally oriented antennae 260, 261, having preferably thesame antenna patterns.

The unit 102 has two outputs 258 and 259, which coincide with outputs ofthe corresponding directional couplers 91, 92, to which the greaterportions of energies of signals of corresponding oscillators 59, 60 arefed, one input 273, coinciding with the input of the phase detector 95,intended for feeding of signal of the reference oscillator 98, and twocontact pins 274, 275, usually electrically connected with each other bymeans of a jumper 276, (electrical connection of the contact group 274,275 by means of the jumper 276 provides electrical connection of outputof the amplifier 257 and the control electrode 101 of the VCO 60 toapply the error signal, formed by the phase detector 95 directly to thecontrol electrode 101 of the VCO 60). In case of the jumper 276 isremoved the mentioned error signal of the phase detector 95 may be fedto one of inputs of signal summator 277, to other input of which it maybe fed a modulating signal (for example, in the form of signal voltagevarying in time). It can provide both phase and frequency encoding(modulation) of the difference signal of signals of oscillators 59, 60,including by information signal from an information source 278 output ofwhich is electrically connected to one of inputs of the summator 277. Inthe last case the oscillator 102 can be used as well in a transmitter ofa telecommunication transceiver). As it was above mentioned (see FIG.14) bands of passage of the units 94, 100 should be selected in such amanner that a modulating (informational signal), arising on the outputof the mixer 93 as a part of the general frequency difference beatsignal, is maximally suppressed and does not pass to the output 269 ofthe unit 268. It provides with a high frequency stability of thedifference signal during intervals when the modulating signal of theoscillator 276 is negligible and guarantees a stability of correspondingparameters of frequency/phase modulating of the difference signal.

Aforesaid unification and notation of aforesaid units are used forsimplifying the subsequent text.

The above-considered generator OMCS and generators, which are analogouswith respect to it and which are based on the principle of radiationpractically from one phase center (of from several centers, but nearlypositioned) of mutual-coherent (two or more) signals, with modulateddifference frequencies may represent a significant practical interest incommunication MMW/SMMW systems. Such systems may find a wide applicationin wireless high-velocity (wide-band) inter-computer communication,relay broad-band communication, for wireless communication of varioussurvival systems inside of buildings, for stealth communication, ifcarrier frequencies of oscillators are positioned in bands of MMW/SMMWradiation absorption by the atmosphere (a stealthiness is also providedby means of forced deviation (it may be in accordance with an accidentallaw) proper of carrier frequencies upon a conservation of the mentionedphasing of the difference frequencies) and so on.

Besides, corresponding receiving and transmitting systems allowsignificantly to concentrate informational channels of communication (bymeans of temporary stability of spectral localization of correspondingdifference frequencies), broadening at the same time both the band ofone of such a channel (phase or frequency deviation of the differencesignal may be as is wished great) and the range of frequencies, occupiedby such channels (an absolute value of the difference signal may be asis wished great, besides a range of carrier frequencies of MMW/SMMWrange in many times exceeds ranges of radio frequencies and microwavesfrequencies. In this case the given device represents by itself atransmitting tract of transceiver with double (or with many) carrierfrequency (frequencies), which may be used for aims of telecommunicationwith an improved noise immunity and without of additional restrictionswith respect a band of informational signal. Besides, it may be used anymodulation/demodulation methods, based on a principle of coherent(improved noise immunity and selectiveness) demodulation of receivedsignals, since the difference frequency, presenting in a signalspectrum, possess of improved phase coherence. (There is a tremendousquantity of approaches to make it discrete one). Phase modulators mayoperate in anti-phase for an increase of depth or effectiveness of phasemodulation.

In such systems by means of signal of communication it is modulated adifference signal (or signals in case of a number of mutually-coherentsignals in the general signal more than two).

For a realization of duplex communication at an output of such atransceiver it may be mounted a frequency diplexer, besides, adifference of transmission frequency and receiving frequency may besufficiently great in virtue of a principle of device realization, andit provides with an improved uncoupling of the transmitting channels andreceiving channels. The uncoupling of the transmitting channels andreceiving channels may be provided also by means of difference offrequencies of corresponding difference signals (correspondingly oftransmission and detection).

The difference signal itself may be modulated by various ways. Thesimplest method is above described in connection with a discussion ofthe OMCS of waveguide realization in accordance with FIG. 14 as well asin accordance with the general circuit diagram of FIG. 51. Themodulators 62 and 63, being a part of corresponding independent signalchannels, may realize both the amplitude modulation of the carrierfrequencies and the phase modulation of the carrier frequencies(besides, at the same time there are used both the modulators 62, 63, oronly one modulator 63, the second carrier frequency plays a part inreference frequency for creation of difference signal in a receivingdevice of transceiver).

Another approach in realization of frequency (or phase) modulation ofthe difference signal consists in an addition of additional signal ofthe communication source 277, modulated with respect to an amplitude, tosaid error signal of the phase detector 95 even if by means of summationof these signals by the unit 276 (for example, by means of summingoperational amplifier or more fast-acting device).

Another capability of modulation of two-frequency carrier consists inthe frequency-phase modulation of signal of frequency of referenceoscillator 98 (the source of difference frequency signal). The frequency(phase) modulation of the difference signal my means of the OMCS (seeFIG. 51) is transferred into the corresponding difference signal. Inthis case a quick-action of device is determined by a realization offeedback circuit of the phase-lock loop.

An anvantages of the last two approaches consists in a simplicity ofintegral and planar embodiment of such a transmitter, when a cost ofoscillators (let us tell on the Gunn's diode) is not high one in virtueof low requirements to a stabilization of their absolute frequencies,besides, the MMW mixer 95 as by the way all the elements of the OMCSdevice may be positioned at the same base (and is carried out by meansof single integral technology as the technology of MMW oscillators).

As constituent voltage-controlled oscillators for aforesaid OMCS it maybe used voltage-controlled oscillators of any type, such as, forexample, microwave field-effect transistor oscillators activated byresonance in a yttrium-iron garnet (YIG) cavity which can changeoperation frequency in wide range, for example, from 8 to 16 GHz, MMWfrequency tunable Gunn diodes oscillators, MMW back-wave tubes,operation frequencies of which can be electronically changed in therange of tens of GHz and central frequencies of which may lie even inTHz spectral range.

Besides, the block diagram of the OMCS may be added by frequencymultipliers, each of which is connected in series by one of independenttransmission channel (see FIG. 51) associated with one ofsingle-frequency oscillators 59 or 60 before and after correspondentmodulators 62, 63 (in this case the modulators should be tuned on acorresponding frequency range of functioning).

The multipliers of frequencies may be realized by usage Schottky'sdiodes, which work as a harmonic generator in this case and which allowsto obtain different order harmonics of fed signal with a quite low levelof looses and which can successfully operates even in THz radiationrange.

Each such a frequency multiplier may be followed by afrequency-selective band (pass-band) filter, passing aonly harmonic ofdesirable order N (further the presence of said band filter issuggested, but in following Figures it is not shown). The usage of thefrequency multipliers makes possible to generate frequencies in anyrange of MMW/SMMW spectrum, which further can be radiated in a freespace by means of antennae 260, 261 (67) (see FIG. 51), in this caseoscillators 59, 60 can operate in microwave spectral range and can beelectronically swept in wide range (for example, it may be a microwavefield-effect transistor oscillator being frequency-tunable byyttrium-iron garnet (YIG) cavity (further referred as YIG oscillators)may be transferred into a MM range by means of multiplication offrequencies with a factor from 3 to 5). The real factor ofmultiplication should not be more than a value of 8 to 10 (otherwise alevel of phase noises and conversion losses begin rapidly to grow,).

One of realizations of generator OMCS 279 with quantity of generatedconstituent single-frequency signals more than two and with differentvalues of their difference frequencies is represented in FIG. 52. Thegenerator OMCS 279 includes oscillators 280, 59, 60 (which can beconsidered as radiating elements) each of which produces asingle-frequency signal, all of the oscillators or, may be, with theexception of one oscillator 280 are voltage-controlled oscillators(VCO). The oscillator 280 is chosen as a master (free running)oscillator at that, phases of signals of other VCOs 59,60 of the OMCSgenerator will be phase-locked on phase of the master oscillator 280 inthe other words VCOs 59,60 being PLL-linked to the master oscillator 280are phase-tied to the master oscillator 280 For providing this fact asmaller portion of power of the oscillator 280 by means of thedirectional coupler 281 is picked off into the waveguide transmissionchannel 282 (being of waveguide or microstrip performance depending onthe realizations of oscillators 280, 59, 60), terminated by means ofmatched load 283 for a minimization of reflections. Set of thedirectional couplers 284, 285 bein coupled to waveguide 282 provideswith a corresponding portion of power of signal of said masteroscillator 280 for correspondent controlling unit based on phase-lockloop (PLL) which is associated with correspondent phase-controlled slaveoscillator like 59 or 60. Said PLL-based controlling units include unitslike units 286, 287, which are functionally completely equivalent toaforesaid second united unit (PLL1) 268 above described in connectionwith FIG. 51, having inputs 288, 289, 290 (belonging to the unit 286)and inputs 291, 292, 293 (belonging to the unit 287), which arefunctionally equivalent to the corresponding inputs 270, 271 and 272 ofthe unit 268, and outputs 294 (belonging to the unit 286) and 295(belonging to the unit 287) being functionally equivalent to an output269 of the unit 268; as well as units 296 and 297, being referenceoscillators generating correspondent difference frequencies referencesignals for said units 286 and 287, being functionally equivalent to theunit 98 (see FIG. 51), but having different frequency values of itssignals. The block diagrams are also provided with directional couplers298, 299, each of which divides the signals of the correspondingoscillators 59,60 into the smaller portions, fed to the inputs 289 and292 of the units 286, 287, but the greater portions are fedcorrespondingly to waveguide 300, 301, which may either directly beconnected to antennae 67, 68 (directional isolators, needed for thiscase, are not shown in FIG. 52), or they may be connected to antenna67,68. To increase frequency of radiating signal frequency multipliers302, 303 may be additionally used which are fed by signals generating bycorresponding VCO 59, 60 and feed correspondent antenna 67, 68 Output ofcoupler 281 associated with master oscillator 280 may be also connectedthrough frequency multiplier 304 to transmitting antenna 69. The masteroscillator may be used also as a local oscillator in receiving part ofimaging system as discussed bellow in the text.

Phase locking of frequency difference beat signal of signals ofcorrespondingly the master oscillator 280 and one of the slaveoscillators 59 (as well as any other slave oscillator) by a signal ofthe reference oscillator 296 is achieved by the following way. to theinput 288 of the unit 296 the smaller portion of the master(free-running) oscillator 280 signal is fed, but to the input 289 ofthis unit 286 the smaller portion of the slave oscillator 59 signal isfed, the unit 286 by analogy with the functioning of the unit 268 (seeFIG. 51) forms a control error signal (correction voltage), which isproportional to a phase mismatch of the frequency difference beat signalgenerated by mixing signals of the oscillators 280 and 59 and the signalof the reference oscillator 296, which from the output 294 of the unit286 is fed to the control electrode 304 of the VCO 59 providing areduction of said phase mismatch up to an attainment of whole phasesynchronism (phase locking) of said frequency difference beat signal andsaid signal ff reference oscillator 296. Thus, frequency difference beatsignals generated from signals the master oscillator 280 andcorrespondingly slave oscillators 59 or 60 will be frequency andphase-tied onto correspondent signals (preferably of the referenceoscillators 296, 297 which can be quartz-stabilized.

In other words, a procedure of formation of multiple mutually-coherent(phase-tied) signals may be described by the following way.

The smaller portion of power of the signal of the master oscillator 280is fed via the directional coupler 281 to the waveguide channel 282,from which portions of the power of this signal via the directionalcouplers 284, 285 are fed to units intended for generating of othermutually phase-coherent (PLL phase-linked) signals. In each such unitthe corresponding signal from the channel 282 is fed to one of inputs ofthe correspondent mixer of the second united unit 286 (which isequivalent to mixer 93 of the unit 268 in FIG. 51). To another input ofthis mixer there is fed a portion of power of signal of the slaveoscillator 59 and, finally, to the first input of the phase detector ofthe unit 286 (being equivalent to the phase detector 95 of unit 268)there is fed the difference frequency signal generated by said mixer andto the second input pf the phase detector there is fed a signal of thereference high-stabilized oscillator 296, the frequency of unit 297 isdifferent with respect to frequency of the oscillator 296. Owing to thefeedback loop, which is provided by means of phase-lock loop (phases ofcorresponding difference signals turn out captured by phases of signalsof the corresponding reference signal). The outputs of the correspondingdirectional couplers 281, 284, through which there are fed the greaterportions of the energies of the signals may be connected to the inputsof the frequency multipliers 304, 302, 303 for a formation ofmutually-coherent signals of higher frequencies.

Besides, a signal of one of oscillators, preferably, signal of themaster oscillator 280, may be used as a heterodyning signal (localoscillator signal) supplied to correspondent mixers of heterodyningmixer units 52 described-above in connection of the FIG. 10 and itssignal may be fed directly to heterodyning input(s) of the mixer(s) ofthe heterodyning mixer units of receiving channels 49 of the receivingdevice 16 (see FIG. 10). At the same time signals of the oscillators 59,60 may be used for an illumination of the diffuser 7 or directly forillumination of the object 9 (see FIG. 1). Signals of the oscillators59, 60 after their reflections from the observed object in theinspection area will be received by correspondent array receivingelements like 47,48 (see FIG. 35) of the receiving device 16 (see FIG.1). The received signals will be mixed in corresponding said mixers ofreceiving channels of the unit 49 with aforesaid heterodyning signalgenerated by oscillator 280 (see FIG. 10). Due to the fact that signalsof phase-locked oscillators 59, 60 are phase-locked onto signal ofmaster (free-running) oscillator 280 constituent frequency differencebeat signals which are formed at the output of such mixers and which areassociated with signals of correspondent reference oscillators 296,297will possess of frequency and phase stability of frequency-distinctsignals of the correspondent said reference oscillators 296,297 (seeFIG. 52) and, as a result, may be precisely extracted from any totalmixer-generated composite beat signal appeared at output of any of saidmixers due to frequency difference between the intrinsic frequencies ofsignals of the corresponding reference oscillators 296,297 (also takinginto account that diffuser cell modulation signals are quite stable andspectrally pure). Moreover they will carry an information both aboutamplitudes and even phases of object-reflected signals. Said amplitude(or intensity) information may be directly used for formation ofsynthesized (combined) image (amplitude information can be determinedfrom said frequency difference beat signals because amplitude of each ofconstituent frequency-difference beat signal included in totalmixer-generated composite frequency difference beat signal isproportional to a length of correspondent radiation phasor, for examplephasor like 197 or 198, shown in FIG. 36, associated with correspondentspectral line like 210 or 211 shown in FIG. 41 or, in other words, to asquare root of value of correspondent spectral density of the spectralline like 210 or 211)), But the information about the amplitude andphase (phasors 192, 193 in FIG. 36 are associated withobject-illuminating radiation but for phasors 197,198 are associatedwith object-reflected radiation really needed for processing) may beused for generating of discussed above three-dimensional image (theabove discussed generator OMCS allows to simultaneously form a couple ofthree-dimensional images when the object is illuminated by signals offrequency-swept oscillators 59,60 which are incident on the object atdifferent angles. The later allows to decrease influence of specklereflections from objects).

In other aspect of invention in accordance with FIG. 53 it may berealized a generator OMCS, in which master (free running) oscillator 280is quite powerful oscillator (for example back-wave tube, Gunn diodeoscillator and so on) operating in MMW or SMMW ranges (which can be usedas a local oscillator for said unit 52 in FIG. 10), but pairedoscillators being phase-tied to said master oscillator 280, which areincluded in OMSC unit 305 being functionally completely equivalent tounit 102 described above in connection with FIG. 51 operates at thefrequencies, for example microwave frequencies, which are essentiallylower than frequency of said master oscillator 280. Such oscillators arethe oscillators of lower frequency, for example, of microwave frequency,which may be realized by technology of, for example, YIG oscillators,which are easyly electronically controlled and frequency-swept in widerange, for example from 8 to 16 GHz. The signals of lower (microwave)frequencies may be transferred into the frequency range of the masteroscillator 280 by usage of corresponding frequency multipliers withcorrect choice of corresponding coefficient of multiplication (harmonicorder)

Therefore in this case two mutually-coherent output signals (one signalphase-locked onto another) generated by the first and the secondvoltage-controlled oscillators of the unit 305, in turn one of which isphase-tied onto another, (being functionally and schematicallyequivalent to phase-locked paired oscillators 59 and 60 of the unit 102at FIG. 51, excepting that both oscillators are VCOs definitely, throughoutputs 306, 307 (see FIG. 53), corresponding to the outputs 258,259 ofthe unit 102, represented in FIG. 51, are fed correspondingly to theinputs of frequency multipliers 308, 309.

And frequencies of the output signals (the output signals of said VCOsof the unit 305 like oscillators 59,60) are independently multiplied bysaid multipliers 308, 309 to make frequencies of correspondent signalsat outputs of the frequency multipliers 308,309 to be equal or to benearly equal to frequency of the master oscillator 280. besides, one(the second) output signal of the second VCO (being equivalent to theVCO 60 of the unit 102) from output 307 of the unit 305 throughfrequency multiplier 309 being frequency-multiplied with factor N issupplied to transmitting antenna 67 for goals of illumination of theobservable object. therewith one portion of another (first) outputsignal of the first VCO of the unit 305 (being equivalent to the VCO 59of the unit 102), which is divided in power by means of directionalcoupler 310 input of which is coupled to output 306 of the unit 305, isfed to the multiplier 308 and after a multiplication of its frequencywith a factor N (as well as after band pass filtration of the multipliedsignal by means of band filter for a separation of the requiredmultiplied frequency with a required factor N of multiplication—thisfilter is not shown in the block diagram as well as such a filter willbe not shown further, although its presence will be suggested) is fed tothe input 312 of the servocontrolling unit 311 which is intended forservocontrolling the frequency of signal of the correspondent first VCOof the unit 305 being equivalent to the VCO 59 at FIG. 51. The referencefrequency high-stabilized signal for the unit 305 is provided byreference oscillator 98 signal of which is fed to input of phasedetector of the unit 305 which is equivalent of phase detector 95 of theunit 102 at FIG. 51. The unit 311 is functionally and schematicallyequivalent to the unit 268 (see FIG. 51), besides its inputs 312, 313,314 are correspondingly equivalent to the inputs 270, 271, 272 of theunit 286 (see FIG. 51), but its output 317 corresponds to the output 269of the unit 268 (see FIG. 51).

So one portion of frequency-multiplied signal (through a band passfilter, which is not shown in the block diagram and which separates themultiplied frequency signal) from the output of the multiplier 308 isfed to the unit 311 being intended for servocontrolling the frequencyand phase of one of the voltage-controlled oscillators 59 of the unit305 (the analogue of the unit 102), used in the block diagram (see FIG.53), to one of the inputs 312 (which is correspond to a mixer inputs 271of the unit 268 in accordance with FIG. 51).

Another portion of the first output signal from another output ofdirectional coupler 310 is fed to input of frequency multiplier 319 andthen after multiplication of its frequency with factor N the multipliedsignal may be emitted through transmitting antenna 68 towards observableobject. To another input 313 of the unit 311 (input 313 is equivalent tothe mixer input 272 of the unit 268 of FIG. 51) by means of directionalcoupler 315 the smaller portion of power of the master oscillator 280signal is fed, and to the input 314 (being equivalent to the input 272of the unit 264 in FIG. 51) there is fed a signal of reference frequencyhigh-stabilized oscillator 316 (the analogue 98 of the unit 268 in FIG.51). From an output 317 (the analogue 269 of the unit 268 in FIG. 51) anerror signal (correction voltage), which is proportional to a value ofphase mismatch between the signal of the reference oscillator 316 andthe frequency difference beat signal of signal from output of frequencymultiplier 308 being equal to frequency-multiplied signal of theoscillator 59 of the unit 305 (102) and the signal of the e oscillator280. The frequency difference beat signal is generated in correspondentmixer being equivalent to mixer 93 at FIG. 51 The frequency differencebeat signal is fed to an input 318 of the unit 305, being an input ofthe control electrode of the VCO being equivalent to VCO 59 at FIG. 51(in this block diagram both the oscillators 59,60 are the VCOs (see FIG.51), Influence of error signal (correction voltage) from output 317 ofthe unit 311 being supplied to controlling electrode of said VCO 59 ofthe unit 305 leads to decreasing of said their mutual phase mismatchbetween said signals up to a complete elimination of this mismatch sothat said VCO 59 is phase-locked to master oscillator 280 while VCO 60of the unit 305 is phase-locked to VCO 59 according to design of theunit 305 described above.

Therewith, the frequency of the oscillator 59 is less than the frequencyof the master oscillator 280 by a factor of N, wherein N is a factor offrequency multiplication of the frequency multipliers 309, 319 (saidfactor is determined by the order of used harmonic). Design oh the unit305 provides that the second VCO 60 of the unit 305 is phase-tied to thefirst VCO 59 and their frequency difference is equal to frequency ofsignal of the reference frequency oscillator 98 (see FIG. 53). Due tothe fact, N-order harmonic of the signal of the second oscillator 60appeared at the output of the multiplier 309 is phase-locked onto thesignal of the master oscillator 280. This fact is based on that theN-order harmonic of the signal of the second oscillator 60 appeared atthe output of the multiplier 309 is phased-locked onto N-order harmonicof the output signal of the first oscillator of the unit 305 (atcorrespondent harmonic of reference frequency of the referenceoscillator 98), the first oscillator, in turn, is phase locked by theoutput signal of the master oscillator 280 at reference frequency ofreference oscillator 316. When frequency difference beat signals will begenerated from aforesaid harmonics and output signal of the masteroscillator 280 each of such frequency difference signals will exhibitspectrally purity and stability being practically compared with puritiesand stabilities of frequency high-stabilized reference oscillators98,316. Said frequency difference signals may be generated in thereceiver channel of the imaging system when the output signal of themaster oscillator 280 is fed to heterodyning input offrequency-down-converting mixer.

Therewith said N-order harmonics are used for illumination of observableobject and after scattering by the object and their focusing by focusingelement of the imaging system they are collected by correspondentreceiving antenna which, in turn, is coupled to signal input of saidmixer. So at the output of the mixer desired frequency differencesignals are generated which carry information on the object in the fieldof view of imaging system. In a simpler realization of OMCS generatorshown at FIG. 54, the PLL1 unit 264 which was above-described inconnection with FIG. 51 is used instead of units 313 and 316. The inputs266, 267 of a phase detector of the unit 264 are equivalentcorrespondingly to the inputs 96,97 of the phase detector 95 of unit 264above-described in connection with FIG. 51. The output signal of thefirst VCO of the unit 305 (being equivalent to the VCO 59 of the unit102 at the FIG. 51) is supplied to the input of the frequency multiplier308 and then being multiplied with factor N the multiplied signal issupplied through the passband filter (which is not shown at the FIG. 53)to the input 266 of the unit 305. A portion of the output signal of themaster oscillator 280 through directional coupler 315 is supplied to theinput 267 of the unit 264. Error signal (correction voltage) beingproportional to a value of phase mismatch between said signals which arefed to correspondingly to the input 266 and 267 is supplied tocontrolling electrode 318 of the first VCO being inside the unit 305(see in detail at FIG. 53). The signal from the output of frequencymultiplier 309 (being N order harmonic of the second VCO signal) isphase-tied to N harmonic of the first VCO at the output of the frequencymultiplier 308 at frequency of correspondent harmonic of referencesignal of the reference oscillator 98, the N-order harmonic isphase-tied to the output signal of the oscillator 280 at zero frequencydistance between them. Besides, such phase synchronization is realizedby means of pair of PLL-linked VCOs operating at essentially lowerfrequencies (it is technically simply) in comparison with the morepowerful master MMW (or SMMW) oscillator 280. From the output of themultiplier 309 (possibly, for selective extraction of harmonic of neededorder, through pass-band of high-pass filter, being not shown in theblock diagram) a signal is fed to the input of the antenna 67 andthrough it into a free space.

It is understood that in the discussed block-diagram it may be addedanother (and not only one) PLL-linked (and phase-locked) paired-VCOsOMSC generator like paired-VCOs OMSC generator 305, outputs of which areloaded by frequency multipliers like the multipliers 308, 309 which isPLL-linked to master oscillator 280 in above-described manner with usagea phase-lock loop of type 264. Said phase-locking of signals of thepaired OMCS onto signal of the master oscillator 280 may be realized byanalogy with the block-diagram shown in FIG. 52 (through the directionalcouplers like 281, 284, 285 ones and the waveguide channel like 282one).

The basic advantages of aforesaid two realizations of OMCS generatorsare in possibility of linking said microwave (centimeter) oscillatorslike 59,60 (or only one 60 in accordance of FIG. 54) with said frequencymultipliers 308,309 through quite long flexible coax cable (which isable to transfer radiation exhibiting frequency up to 36 GHz and whichat points of connection with the multipliers and may be withcorrespondent harmonic mixer have to be provided with simple matchingfrequency selective circuits to pass any required signal through withoutreturns including biasing signals—some bias tee). This is essential fordesigning of imaging systems because correspondent said heterodyningmixers 52 of the FIG. 10 where oscillator 280 may be used as a localoscillator) while the illumination part of the imaging system(illumination source 2, diffuser 7) is disposed at some space distanceapart the receiving device. So frequency multipliers 308,319 feedingcorrespondent transmitting antennas 67,68 may be disposed in a place ofdisposition of the antennas which face to a diffuser 7 or directly anobserved object 9 (see FIG. 1). This is important because header ofillumination consisting of radiation antenna like 67 and antenna-coupledfrequency multiplier 309 sometimes, needs to be located quite far (1-3meter and more) from the OMSC generator and receivers of imaging systemand needs to be easily reoriented for illumination the observable object9 and different portions of a diffuser 7 (FIG. 1). Such connection isimportant for suitable supply a local oscillator signal to receiverdevice without usage of rigid waveguides (case of OMCS being shown atthe FIG. 52).

Such an approach allows to solve problems of adaptation of aforesaiddevices for both receiving and illuminating goals, since a flexiblecoaxial cable allows to easily replace within a light header, consistingof frequency multiplier, l\feeding a transmitting antenna, and to locateit in anyone point, which is optimal one for the diffuser- orobject-illumination. It is essentially also that various oscillators ofmutually coherent signals like 59, 60, . . . oscillators (see FIGS. 52to 54) may independently and technically simply illuminate spatiallydistinctive portions of the diffuser for example portions 160 and 161 inFIG. 30 and FIG. 37., wherein the portion 161 of the diffuser may beilluminated by means of beam of radiation generated by the oscillator59, but the diffuser portion 160 may be illuminated by means of beam ofthe source 5, but the portion 161 will be illuminated by means of thesource 4 in FIG. 52 or in FIG. 53. Such illumination provides distinctencoding of radiation portions, reflected from said diffuser portions,since in the receiving device after mixing received signals with theheterodyne signal of the oscillator 280 (which can be a local oscillatorshown as 52 at FIG. 10) in a simple mixer or a harmonic mixer of thereceiver device of the imaging system. The encoding takes place due tothe fact that at the output of said mixer distinct intermediatefrequency signals (frequency difference beat signals) will appear whichwill be shifted from the origin at frequency axis at frequency valuesequal to frequencies of reference frequency signal of correspondentreference oscillators 296, 297 (FIG. 52). The latter providespossibilities to distinctly select each of the signals by means offrequency selective electronic circuits in any point of receiverchannels of the receiver device 16 (FIG. 10) and then determine theirparameter like intensity and so on.

A composition and mutual sequence of electronic modules, being includedin each of corresponding receiving channels of the receiving device 16(see FIG. 1), depends on type of encoding of radiation partialcomponents used for illumination of observable object which will befinally received by antenna receiving element 47 of receiving array 46being coupled to correspondent receiving channel of receiver device andwhich “looks” at the correspondent part of object surface 187 (see FIG.35) of object 9 which reflects said radiation partial components. Thepartial radiation components may be primarily encoded (for example bymeans of amplitude modulation) to distinctly label radiation emittedwith different radiation sources like 3,4,71 (see FIG. 35) and thensecondary encoded by radiation-encoding diffuser when the primarilyencoded radiation components are reflected by spatially distinctportions of the diffuser which provide distinct secondary amplitudemodulation of scattered radiation. Generally, decoding (for exampledemodulating) of doubly encoded (for example doubly modulated) signalsresponsive to received doubly encoded (for example modulated) radiationcomponents is not technically difficult and may be realized with usageof conventional electronic modules such as mixers, square-law detectors,synchronous (parametric) detectors which can be swept in frequency.Moreover, decoding (for example demodulation) of the encoding (forexample modulated) may be realized by digital processing methods whichare applied to received signals which may be primarily frequencydown-converted enough for digitizing, amplified and then digitized bymeans of suitable analogue-digital converter and loaded into memory ofdigital processing means for following processing/. Digital approach maybe successfully realized for any kind of decoding/demodulation ofencoded/modulated signals.

The OMCS generators allow to realize novel possibilities in forming ofimaging systems and transferred of the acquired imaging information bymeans of communication systems. The application of the oscillators ofmutually coherent signals for both the aims of the encoding illuminationof the objects and decoding of received signals (upon theirmutually-coherent heterodyning) in channels of receiving device allowsto attain principally novel abilities both as to the volume ofinformation obtained from such signals and as to increasing ofsensitivity of receiving channels and its dynamic range.

For understanding details of encoding (for example, modulation)/decoding(for example, demodulation) procedures let us discuss the peculiaritiesof generation of frequency difference beat signals, exhibiting highspectral purity and frequency stabilities, in one of receiving channelsof the receiving device after their propagation from a radiating antennaof corresponding partial source element 3 (4, . . . ) of radiation tillthe receiving array 46 and upon their receiving by one of the elements(receiving antenna) 47 of this receiving array 46 (see FIG. 35).

The frequency difference beat signal for signals of the PLL-lockedoscillators of OMSC generators discussed above, may be produced in thereceiving device of imaging system by means at least of two distinctivemethods. In the first case both the radiation components (spectralcomponents), generating by correspondent paired VCOs are receivedtogether by receiving antenna after their almost the same propagation infree space or in free space, inspection area and inside imaging systemSuch doublet signal can be presented as a double carrier signal used intelecommunication system or a doublet radiation signal, used forilluminating in the imaging system. After their receiving the doubletsignal paired components are concurrently frequency down-converted andamplified and then are fed to square-law detector (some non-linearelement, for example a diode) which is included in the receiving channelassociated with receiving element 47 said antenna of which have receivedsaid doublet signal. Besides said amplification channel may compriseanyone combination of amplification and frequency-converting units,positioned in the amplification unit before the square-law detector, ifsuch units transform both paired component of the doublet signalequally. Said square-law detector will be capable to generatepractically the same frequency difference beat signal from said doubletsignal in any case if its paired components are amplified enough inspite of the fact they were previously frequency-converted or were not.The generated said frequency different beat signal may be furtheramplified and frequency-down converted additionally conserving itsamplitude and phase content.

In the second case there are used mixers (or parametric detectors, forexample, synchronous detectors), signal input of which is fed by one(the first) component of said paired components of doublet signal whichwas used for illumination goals and propagated from transmitting antennalike 67 in FIG. 52 to scattering diffuser then to lens of imaging systemand then to an antenna of a receiving element like 47, whileheterodyning input (or reference input of the synchronous detector) ofthe mixer is fed by another (the second) component of the doubletsignal, which is phase-locked onto the first component. The secondsignal component is propagated via, for example, flexible coax cable orby another way with conserved amplitude and known phase delay appearingdue to differences in paths of propagation of the components.

For an electric signal, which induced in output of an receiving antenna47 of the receiving array 47 by partial radiation component whichexhibits radiation features α_(l) ^(d) (notation here is the same as inrelationships (5)-(15) excepting that index t is substituted with indexl) is amplified (and may be frequency down-converted) and feeds to theinput of the unit (like square-law detector) intending for generatingaforesaid frequency difference beat signal between the signal and signalbeing phase-locked to one, may me written that $\begin{matrix}{{{{}_{}^{\alpha 1d}{}_{i,j}^{}}(t)} = {{{}_{}^{\alpha 1d}\left. V \right.\hat{}_{i,j}^{}} \cdot K \cdot {\exp\left( {i \cdot \left( {{{}_{}^{}{}_{\alpha ld}^{i,j}}(t)} \right)} \right)}}} & (17)\end{matrix}$Where in total phase value is equal $\begin{matrix}{{{{}_{}^{i,j}{}_{\alpha ld}^{}}(t)} = {\left( {{\omega_{\alpha_{l}^{d}}^{b} \cdot t} + {{{}_{}^{}{}_{\alpha ld}^{}}(t)}} \right) + {{{}_{}^{}{}_{\alpha ld}^{}}(t)} + {{{}_{}^{}{}_{\alpha ld}^{}}(t)} + {{{}_{}^{i,j}{}_{\alpha ld}^{}}(t)}}} & (18)\end{matrix}$in this case it is omitted a pair of indexes (m,n), showing a positionof receiving element in the receiving array 46, instead of them there isintroduced the index b=1,2 showing an order number of paired componentin the doublet (1 or 2) or it demonstrates the fact that the componentis fed into the receiving device as a reference signal b=0 (see below).K is a total coefficient of amplification of the receiver channel whichcan includes different amplification/ frequency downconversation unitsbeing disposed before said frequency difference beat signal-generatingunit (including said receiving antenna), . . . is amplitude of (phasoramplitude) of partial radiation component, received by the antenna,wherein (i,j) is an index of diffuser element, which have scattered thesaid partial radiation component (it is used only if the diffuser isused, otherwise it should be omitted); . . . is a central frequency ofpartial radiation oscillator, but—is its phase noise, characterizingdeviations of real frequency of this oscillator from its central value.If the mentioned amplification-frequency/downconversation units includeany heterodyne mixer(s) (especially in a case of amplification ofdoublet radiation signals) local oscillator of which has a frequencyD(t), in the relationship (18) instead of the frequency . . . it shouldbe written −D(t), however, such a replacement do not affect a result,when it is down-converted a doublet signal because value of frequencyD(t) of any local oscillator can not change a frequency of frequencydifference beat signal of paired components of a doublet signal. It isexplained by the fact, that while down-converting the value of frequencyof the local oscillator is subtracted from values of frequencies of eachcomponent equally. As a result frequency value of the local oscillatorcancels itself from the value of frequency of a frequency differencebeat signal when the beat signal is generated from said pairedcomponents. The last fact is important, since it allows to usefrequency-unstable inexpensive heterodyning local oscillators forfrequency down-conversion of doublet signal into intermediatefrequencies without affecting quality of frequency difference beatsignal between its components;

-   -   determined phase addition value appeared due to of special phase        modulation of partial radiation components (if it takes a        place), which is added in a signal in any of the above-described        methods, mentioned in connection of FIGS. 52 and 53;    -   phase addition, value appearing as a result of radiation        propagation in any free space between a radiating antenna of        element of radiation of illumination subsystem and a receiving        antenna of the receiving element 47; and    -   phase addition, value introduced in a signal by a diffuser cell        (if in an illumination subsystem there is used a diffuser),        besides, if the diffuser only capable to destruct a spatial        coherence of incident radiation, dispersed by it, the phase        addition is an accidental function of time, if the diffuser is        encoding one, it is a regular determined function, wherein . . .        -a frequency of signal modulating (i,j) cell (element) of the        diffuser.

Being a part of the described-above total phase value a phase noise ofone radiation component of the doublet generated with correspondent (thefirst) VCO of the OMSC generator is equal to phase noise of anotherradiation component of the same doublet generating by another VCO of theOMSC generator because the first VCO is phase locked onto another so thevarying in time phase noise of the one radiation component is phase-tiedonto another radiation component, so one following another,

-   -   (19)

Since the generated frequency difference beat signal depends ofdifference of total phase values of paired components of the doubletsignals and with an accuracy up to constant d is described by thefollowing correlation:

-   -   (20)

So the above-mentioned phase noises of the radiation components cancelthemselves in the generated frequency difference beat signal but anotherphase additions which are different for different radiation componentswill be not equal to zero and this fact may be used in differentapplications.

So, when constituent oscillators of OMCS generators like described aboveare used for both for illumination goal and receiving goal and when theone VCO (from OMSC in FIGS. 51-53) for example 59 is used forillumination the diffuser (or its part), b=1 in this case, but other VCOfor example VCO 280 is used as a local oscillator for the correspondentmixer, b=0 in this case, the frequency difference beat signal appearedat the mixer output will be written by the following way

-   -   (21)

wherein frequency of the frequency difference beat signal is equal tosum of a stable constant frequency being equal to the frequency ofreference oscillator 98 used in the correspondent OMSC generator, and afrequency of modulation signal modulating said diffuser cell (i, j).which can be quartz stabilized like reference oscillator 98. Due toknown frequency values for all said diffuser modulation signals thestrictly-determined frequency shift of correspondent spectral line 211(see FIG. 41 with taking into account that all spectral lines of theFigure are shifted into frequency range of frequency difference beatsignals) responsive to the partial radiation component created due tomodulation of radiation during its reflection by said diffuser cel (l,j)may be easily determined This spectral line and any other spectral linesof the total frequency difference beat signal spectrum will be stable(with accuracy of stabilization from 1 to 10 Hz and less for example) asgood as correspondent reference oscillator 98 and its bandwidth will becompared with bandwidth of this signal of reference oscillator 98. Thisfacts will provide very narrow bandwidth of frequency band 212 (beingshifted into the spectral range of frequency difference beat signals)occupied by all beat signals appeared due to all diffuser cells(independent encoding diffuser elements) even if the total number of thediffuser radiation-encoding cells will be great. The narrow bandwidth ofpossible band for all frequency difference beat signals will provide lowlevel of noises of receiving electronic apparatus its very importantbecause the frequency difference beat signals will be very stable infrequency as well.

Form of the spectrum (212) helps to find possible optimal arrangementsof amplifying, frequency downconversion and demodulating units inreceiving channels of imaging system receiving device which will allowto extract information on each of the spectral line like 211 fromantennas-received signals.

One of simple arrangements of such units is shown in FIG. 55, in whichobject-reflected signals being received by antenna 321 are fed through aMMW amplifier 322 (including band filter 323 and amplifier 324 to signalinput of first mixer 325 (in other aspect of the invention the receivedsignals may be fed directly to said mixer input without usage said MMWamplifier). For definiteness it is proposed that the object areilluminated by the signals being primarily generated by VCOs like 59 or60 and fed to transmitting antennas 67,68 through frequency multipliers309,319 (which increase signals frequencies) of OMSC generatorsdiscussed above in connection of FIGS. 53 and 54. While the heterodyninginput 326 of said mixer 325 are fed by signal produced by masterfree-running oscillator 280 (FIGS. 53, 54). (In cases when for feedingthe heterodyning input 326 of the mixer 325 it is used a microwave VCOlike 60 of the unit 305 in FIGS. 53, 54 then either said mixer 325 is aharmonic mixer operating at suitable harmonic order N or theheterodyning input is fed through frequency multiplier operating atsuitable harmonic order N which is physically disposed near the mixer325).

The beat signals of difference frequencies, obtained at the output ofthe mixer 325, are fed to the inputs of the independentfrequency-selective channels like channels 327, 328, realizing afrequency separation of the produced constituent frequency differencebeat signals by such a way that each of said channel is capable to passsignals with frequencies disposed near a frequency being equal tofrequency of a correspondent reference oscillator of the used OMCSgenerator like reference oscillator 98 in FIG. 54 said signals arefiltered by frequency-selective amplifier 329 (330) (each of which maybe characterized correspondent band filter and amplifier). At that eachof said frequency-selective unit exhibits central frequency and passbandadjusting for passing, a frequency difference beat signal of some groupof such frequency difference beat signals which are associated only witha particular VCO like 59 0r 60 of correspondent OMCS generator (a singlefrequency difference beat signal appears when a radiation-encodingdiffuser is not used in imaging system and a clustered set of themappears when such a diffuser is used). Further in each of saidindependent channels 327, 328 it is carried out a parametric detectionof correspondent channel-selected frequency difference beat signalswhich are fed from output of unit 329 to signal input 330 of the secondmixer 331 in correspondent channel 327 (in this case the beatfrequencies are associated with signal of VCO 59) but heterodyning inputof the second mixer 331 are fed through tunable phase shifter 333 bysignal of correspondent reference oscillator of used OMCS generator (forexample, reference oscillator 98 in FIGS. 51,53,54 or 296,297 in FIG.53) via, for example, coax cable. Generally the reference signal may beanyone (taking into account that correspondent OMCS generator have tooperate stable with such reference signal which can be even frequencymodulated signal. The later allow to make requirements for dynamic rangeof receiving channel to be not so strict). In preferable embodiment ofinvention said reference oscillator is quarts and termo-stabilized withfrequency accuracy less then 1-10 Hz.

On an input of the second mixer 331 there appears a signal being a sumof partially demodulated signals responsible for partial radiationcomponents scattered with different radiation-encoding diffuser cellsspectral amplitude of which are correspondent to correspondent spectralamplitudes of spectral lines 211, 210 (see FIGS. 41 and 43) ofradiation, scattered by correspondent cells (elements) 10, 11 of thediffuser 7 (see FIG. 39) and further reflected by means of correspondingportion of the object 9 surface (see FIG. 1) while frequencies saidpartially demodulated signals equal to frequencies ω_(i,j) of modulationsignal modulating of the corresponding (i,j) cells (elements) 10, 11 ofthe diffuser 7 (see FIG. 1). It allows after their filtration by meansof the frequency-selective amplifier 334 (the filter 335 and amplifier336) exactly to determine their spectral amplitudes of partiallydemodulated signals (values of radiation spectral density 210,211 or inother words a square of amplitude of, phasor 197,198 (see FIG. 36). Saidspectral amplitudes will be proportional to the intensities ofcorrespondent partial image at position of the antenna receivedaforesaid signals.

Such determination may be realized by means of the following ways:

in the first case it may be made by means of a quadrature-based (I/Q)phase-locked synchronous detector 337, to a signal input 338 of which itwill be fed said sum signal (as an additive mixture of said spectrallydistinctive partially demodulated signals produced by a second mixer332), from an output of a filtering unit 334, while input of filteringunit 334 is connected to an output of the second mixer 332, but to areference input 339 of the quadrature-based (I/Q) phase-lockedsynchronous detector 337 there is fed a reference locking signal ofexternal source being frequency-scanned in the range of frequenciesω_(i,j) of signals modulating the said cells (elements) 10, 11 of thediffuser 7. Signals from “I” channel 340 and “Q” channel of thesynchronous detector 337 are fed to inputs of a computing unit 342,calculating from the signals a spectral amplitude of that partiallydemodulated signal of said sum signal being fed to an input 338, afrequency of which currently coincides with a frequency of the scanningreference locking signal, fed to an input 339 of the synchronousdetector 337. A signal from an output of an unit 343 may be fed to theinput of the multiplexer 50 (see FIG. 10);

in the second case total said sum signal may be fed from an output ofthe second mixer like 331 through said filtering unit like 334 to input344 of an analogue-digital converter 345 (which digitize said signalduring some digitizing duration time) which convert said temporal sumsignal in some finite set of temporal samples. After loading the set ofthe digitized samples in memory of the processing and digitizing means349 further said sample set may be processed by means of digital FurrierTransformation to extract information on aforesaid spectral amplitudesof frequency-distinct constituent signals responsible for aforesaidpartial radiation components received by said receiving antenna whichare distinctly modulated by various diffuser cells. Spectral accuracy ofsuch determination will be reciprocal proportion to said digitizing timeand limited to bandwidth of spectrum of signal of said referenceoscillator 98. Processed information may be fed from an output 348 ofthis digital unit 349 directly to the central processor 56 (see FIG.10).

In other aspect of the invention it may be obtained information both onamplitudes of said spectral lines (radiation spectral densities) andamplitude and phase of partial radiation components (total phasorinformation) associated with said spectral densities. In this case atotal said sum signal have to be fed from an output of the second mixerlike 331 through said filtering unit like 334 to input 344 of ananalogue-digital (A/D) converter 345 (which digitize said signal duringsome digitizing duration time) and said A/D converter 345 almostconcurrently (or another A/D converter operating synchronously with thefirst A/D converter 345) have to digitize and at the same time it shoulddigitize the reference locking signal, fed to the reference input 332 ofsaid mixer (of 331 type) (in this case a frequency shifter of 333 typeis not necessary in the block diagram), which also should be fed on theinput of the A/D converter (through a multiplexer or it should be fed onthe input of said second A/D converter). In this case a processor 347 ofprocessing/digitizing means 349 from data, loaded from the input(s) ofthe A/D converter 345 into the memory 345, may separate both theamplitude and phase information amount the signal on the input of themixer 331 by digital methods (the phase information will present randomfunction if it is used a diffuser randomly destroying spatial coherenceof radiation and will present regular function is used diffuser isradiation-encoding one.). In case of multi-parametric image formation itmay be used only the information about the signal amplitude.

It should discussed additionally a case, when for goals of illuminationof the diffuser (or object) and simultaneously for feeding heterodyninginput of mixer of receiving device signals generating by OMCS generatorsdiscussed above are used. In one case only phase-locked VCOs like 60operate at frequencies being less than operating frequencies of imagingsystem by a factor N (FIGS. 53 and 54). In another case even operatingfrequency of their master free-running oscillator (FIG. 52) is decreasedin N times. While operation frequencies of imaging system are formedfrom frequencies of said oscillators by means of feeding frequencymultipliers operated at a factor N of multiplication (it may befrequency multipliers like 302 to 304 in accordance with FIG. 52 or of309, 319 in accordance with FIGS. 53 and 54). In this case a receivingblock diagram (see FIG. 55) should be modified, So, if operationfrequency of the master oscillator 280 (see FIGS. 54 and 55) coincideswith the operation frequency of the system for imaging, the heterodyninginput 326 of the mixer 325 should be fed directly by a signal of theoscillator 280, however, the heterodyning input 332 of the mixer 331should be fed through frequency multiplier by a signal of the referenceoscillator 98 frequency of which is primarily increased by a factor N.and then selectively filtered (the units for multiplication andfiltration are not shown in the block diagram) (in this case the unit333 may demonstrate said multiplier and filter in providing that thecorresponding phase shifter is not shown or it is absent).

If all the oscillators of the OMCS (see FIG. 52) operate upon reduced(for example microwave) operation frequencies the reference input 326 ofthe mixer 325 is fed either by a signal of the oscillator 280 beingprimarily multiplied in the corresponding frequency multiplier 304 by afactor N (see FIG. 52) or is fed directly by a signal of the oscillator280, however, the mixer 325 in the last should operate as a harmonicmixer at harmonic order N. The reference input of the mixer 333 as wellas in the above-discussed case, should be fed by a signal of theoscillator 98, multiplied by N times in correspondent frequencymultiplier. In this case the diffuser or object have to be illuminatedby means of signals of phase-locked oscillators 59, 60, multipliedpreliminarily by means of frequency multipliers 309, 319 (see FIGS. 53and 54) or multipliers 302, 303 (see FIG. 52).

The above-discussed block diagram may be used for an obtainment ofcomplete amplitude and phase information about the OMCS source 59signal, reflected from the object and focused on the receiver (see FIGS.52 and 53), used in this case immediately for the object illumination(it is necessary for a formation of the above-describedthree-dimensional images of the first type). In this case the signal ofthe oscillator 59 immediately illuminates the object, and the signal,reflected by the object, is focused on the antenna 321 (see FIG. 55) ofthe element 47 of the array 46 (see FIG. 35). Further as well as in thedescribed block diagram the signal either at once is fed to the signalinput of the mixer 325, or after an amplification by the unit 322,besides, the phasing signal of the oscillator 280 as well as in theabove-described block diagram is fed to the heterodyne input of the unit326 of the mixing unit 325. The obtained difference signal from themixer 325 output passes through the intermediate frequency amplifier 329(if one channel of processing of difference signals is used or throughthe corresponding intermediate frequency amplifiers like 329, if thereare used several channels of processing); further a signal from anoutput of a band frequency transformer is immediately fed to the signalinput 338 of the synchronous quadrature detector 337, but to thereference input 339 of the synchronous quadrature detector 337 there isfed a signal of the stabilized source 98 from the used block diagram ofOMCS (see FIGS. 52 to 54) (possibly through an additional controlledphase shifter (not shown in FIG. 54) for a compensation of the signal 98increment in a coaxial cable) is fed to the reference input 339 ofsynchronous detector 337. The quadrature signals, formed in the detector337, through its quadrature outputs 340, 341 are fed to the computingdevice, calculating both the amplitude and phase of the signal (buttherefore also a spectral density even in case, when the signal phase isaccidental one (upon the frequency, that equals to the frequency ofsignal of reference oscillator 98), fed to the input of synchronousdetector 37 (but well then also on the input of the antenna element 321)for each novel frequency of the oscillator 59 signal, swept by radiationfrequency (besides, the frequency of the follower oscillator 280 incorresponding OMCS changes in concord by phase in accordance with theOMCS realization). The obtained set of complex signals (for eachfrequency of the oscillator 59 scanning in the set there is acorresponding complex signal) is fed into the central processor 56,wherein it is subjected to the Furrier transformation by a set ofcomplex values from the scanning frequency of the oscillator 59,transferring so this set into the information about a coefficient ofobject portion reflection, on which through a focusing lens the antenna321 “looks”, and about a depth of this portion deposition along anoptical axis of this focusing lens (in accordance with a theory ofmulti-frequency radars with a synthesization of main band).

In FIGS. 55 to 59 there are represented block diagrams of input units ofthe receiving channel of the receiving device 16 (see FIG. 1), allowingto amplify, to downconvert and partially to decode antenna-receivedsignals (including doublet signals) the later may be perform by usingsquare-law detector or by mixer (and parametric detector). At that Itmay be decoded frequency difference beat signals exhibitinghigh-stabilized central frequency and envelop of which contain allinformation on correspondent pixel of correspondent partial image orinformation of telecommunication signal. Such partially decoded signalsmay be supplied to input units considered above for their completedecoding for example by means of units 327, 339, and 329 or 329 and 349and so on.

In FIG. 56 there is presented input part of super-heterodyne receivingdevice, consisting of receiving antenna 321, electrically connected to aDikke switch 350 (intended for additional amplitude modulation of inputsignals. The element 350 is needed really for radiometric systems, foractive system it is not necessary element), which in turn, is connectedto an MMW amplifier 322, which is, in turn, in series is connected tothe mixer 325, heterodyne input 326 of which is fed by local oscillator.A frequency of the local oscillator should differ from a possibledifference frequency of frequency difference beat signal which can beproduced from paired components of a doublet signal (if the receivingdevice is used for amplification, heterodyning and processing of doubletsignals). Besides, in the most general case connected with usage ofdoublet signals this local oscillator may be quite unstable and may nothave any connections with VCO like 59 or 60 of used OMCS generator. Theoutput of the mixer 325 is electrically connected to the input of theintermediate frequency band amplifier 329, for frequency-selectiveamplification of the downconverted received signal, being shifted downby frequency of the local oscillator signal. In principle, there may beused some set of heterodyning down-converted stages linked one toanother in series) by usage, for example a second mixer followed bycorrespondent band amplifier which are not shown in FIG. 56). In thiscase the first mixer 325 and first intermediate frequency amplifier 329may be used for an effective suppression of mirror (Image) componentsand different inter-modulation components, appeared due to thedownconversation the second mixer and correspondingly the second bandamplifier (they are not shown in FIG. 56) may possess better selectionrequired signals and better noises. The units 322, 325 and 329 togethermake a typical unit 351 of amplification and heterodyning ofantenna-signals, besides, such a unit may not include amplifier 322, andan antenna-received signal may be fed directly to the input of the mixer325. The output of the intermediate frequency amplifier feeds an inputof square-law detector 352 of signals (amplitude detector like a diode),which produce frequency difference beat signals from paired componentsof any doublet signals (square law detector will provide producing anenvelop for single carrier amplitude-modulated signals) due tomultiplication one said component by another component being mutuallyphase locked (as a result of non-linear transformation), which wereindependently received by the antenna 321 and were transformed by theabove-mentioned stages for signal amplification and down conversion.

As it was above-mentioned, noises of the heterodyne local oscillators donot add phase noises in the frequency difference beat signal, since theyare equally added in both the components of doublet signal and thencancels themselves are mutually excluded after a non-lineartransformation by square-law detector 352. The latter is important alsofor telecommunication systems, since it does not require any frequencystabilization of heterodynes and differ from a conventional receivingand transmitting equipment. Further the formed frequency difference beatsignals may be processed (by means of anyone of the above-describeddecoding units 327, 337, 342 or even by their modules 339, 342, 345depending on type of encoding of transmitted doublet signals.

It should be specially noted that the block diagram (see FIG. 56) inessence completely corresponds to a input stages of conventionalradiometric receiver, a square-law detector diode 352 is able to detectradiation emitted within observable scene. Thus, such a receiver can beused both for formation of radiometric images and active encoded images.A difference may consists only in different limitation of pass bandwidthfor used selective amplifiers. However, upon a combined usage of such areceiver limitation for narrow-band pass-banding may be realized inamplifying stages followed the square-law detector 352 and it can allowto receive and process signals of both passive and active images in onereceiving channel.

In FIG. 57 it is shown a particular case of a receiving block diagram inaccordance with FIG. 56, in which it is absent a MMW amplifying unit(usually of waveguide realization), but signals, received by the antenna321, are fed to the input of the mixer 325 (as it was above mentioned),

As it was mentioned, besides, said amplification channel may be compriseany combination of amplification and frequency-transformation units,positioned before a square-law detector, if their influence on both thecomponents of the corresponding doublet signal is equally one. Then asquare-law detector will be capable to separate from said doublet signalits frequency difference best signal with conserving mutual spectral andphase composition. Furthermore, as it was mentioned, the producedfrequency difference beat signal may be additionally amplified in one orseveral stages of amplification and downconversion (consisting of mixeran corresponding intermediate frequency amplifier) when local oscillatorsignals for the stages are chosen by specific way to save said mutualspectral and phase information. It may comprises several frequencydownconversion changes, each achieved with ussage of a local oscillatorbeing phase-referenced. These references may be obtained by frequencydividers cascading from the reference signal supplied by correspondentreference oscillator 98 of used OMCS generator. As a result all saidlocal oscillator are phase-stabilized on the signal of the referenceoscillator.

The same heterodyne amplification of the frequency difference beatsignal is also possible in the block diagram of FIG. 55, wherein thefrequency difference beat signal is produced in the mixer 325, a localoscillator signal for which is a signal of the master oscillator 280 ofthe corresponding OMCS (see FIGS. 52 to 54). So in this case toprecisely conserve a mutual spectral and phase content in produced saidfrequency difference beat signal additional stages of theamplification/downconversion of the, signal have to use phase-referenced(-tied) local oscillator signals which can be realized, for example byfrequency dividing of signal of said reference oscillator 98.

As aforesaid input part of the receiving channel may be used unitsrealizing principle of direct amplification and detection of receivedsignal sa shown in FIG. 58.

The latterly developed technology of production of low-noisy amplifiersof MMW range (up to 140 GHz an over) allows to amplify a signal up to avalue, essentially exceeding a level of the square-law detector(non-linear transformer) 352 noises, and it allows to realize adetection of the amplified signals of MM frequency without any using ofany cascades of preliminarily signal heterodyning. In this casemutually-coherent doublet signals, received by the antenna 321 (see FIG.58), are amplified in the ultra-high amplifier 322 on the carrierfrequency of 40 to 50 dB and over and are fed to the non-lineartransformer (like a diode) 352, separating owing to its upward amplitudecurve squareness the corresponding signals of difference frequencies.

The block diagram of receiving device, shown in FIG. 58, represents asignificant practical interest from a standpoint of fast and effectiverealization of the above-described approaches in a formation ofmulti-parametric high-informational images by means of intensivelyworking out at the present time millimeter radiometric multi-elementcameras, operating in real time. Such MM multi-element cameras (havingup to 1024 and over of receiving independent elements), amplificationchannels of which are constructed on the base of integral technology andon the base of the above-described principle of direct amplification anddetection of signals, are capable to form multi-element-images with avelocity of up to 17 sequences per second and over and with asensibility of 1 L and over (such a camera is worked out, in particular,by TRW in the USA). Advantages of such a camera consist in capabilitiesof decreased density of three-dimensional packaging of channels forreceiving and amplification of signals of MM images. It is attainedowing to the absence of powerful heterodyne signals, an powerdissipationof which always requires a decrease of density of the amplificationchannels and correspondingly a decrease of spatial resolution of camera.

However, such cameras are intended for an obtainment of only passiveimages an realize a radiometric principle of radiation receiving.

It is known that the formation of the radiometric images inside ofclosed premises (wherein all the procedures of concealed inspection arecarried out) is absolutely ineffective owing to a low contrast ofbrightness temperature of observed articles (5 to 7 K), therefore thementioned camera may operate only outdoor under conditions of contrastbacklighting of objects by “cold” sky (77 K) and by “hot” surface of theearth (300 K).

Taking into consideration peculiarities of functioning of theabove-described modules 327, 337, 342, 349 for decoding signals inaccordance with FIG. 55 as well as taking into account peculiarities ofthe block diagram for the direct amplification and detection inaccordance with FIG. 58, it would be stated that such MM televisioncameras may be technologically simply adapted for the above-discussedactive multi-parameter imaging so active cameras may operate in realtime. Besides, the modiles 327, 337, 342, 349 may be used as non-complexlow frequency units of terminal stages of the amplification channels ofthe receiving device which follow the diode 329, ptoducing requiredfrequency difference beat signals.

Thus, such a camera may be effectively used not only for a formation oflow-contrast radiometric mages without any real information about theobjects, being in closed premises, but also for a formation of activeimages with an increased informational content, which are capable to beobtained under any conditions.

The considered principle of generation the mutual coherent pairedfrequency-shifted signals allows effectively to use the directamplification and detection circuits as a receiving part of anyoneMMW/SMMW transceiver without any additional localoscillators-heterodynes upon a conservation of high reliability andfast-action in a receiving/transmitting of data.

The receiving and decoding of doublet signals (i.e., the signals,consisting of the pair of mutually-coherent signals being phase tied oneonto another) may be effectively realized by means of receiving arraysof antennas loaded by non-linear elements (for example by Schottky'sdiodes) (see FIG. 59). In such receivers aacross antennae termonalsthere is mounted a non-linear element (the Schottky's diode) 353,connecting, thus, paired conducting antennae elements 354, 355.Constructions of such receiving element may be schematically illustratedalso by FIG. 15 in case of using antenna-associated non-linear elementshown in FIG. 15 for aforesaid receiving and non-linear transforming(square-law detection) of the input signals. Such an antenna-associatednon-linear element may be used also for a quasi-optical heterodyning ofthe input signals (in the last case the heterodyning signalquasi-optically impinges to the receiving antenna 354-355 together withthe input signals and on the antenna and on output of this element (onantenna terminals) there appear a corresponding intermediate frequencydifference beat signal). In case of the usage of this element as a mixerto the antenna terminals it should be additionally connected a matchedcircuits (planar band filte)r for a separation of the formedintermediate frequency signal, and biasing of the non-linear element 353in this case is also provided via this circuit.

Another variant of heterodyning of the doublet signals on theantenna-associated non-linear element (see FIG. 59) is based on therealization of three-frequency heterodyning. In this case on theantenna-associated non-linear element together with inputmutually-coherent doublet components there is fed the third heterodynesignal of additional oscillator 356, a frequency of which by ordercorresponds to a frequency of difference signal of said doubletcomponents (see FIG. 59), but the sequential band intermediate frequencyamplifier 329, electrically connected to said antenna-associatedelement, has a final pass ban (corresponding to the difference signalband) with a central frequency, that equals to a difference of thedoublet difference signal and to the third heterodyne signal ofoscillator 356. Such a mixing element in consequence of three-frequencymixing creates the second difference signal, being situated in a band ofsaid intermediate frequency amplifier. Since the first difference signal(between the doublet components) may have a frequency up to 1 GHz andover, the frequency of the heterodyne signal may be situated in an areaof hundreds of MHz, and it provides with a high value of the seconddifference signal frequency and correspondingly provides with all theadvantages of super-heterodyne block diagram of receiving. Losses oftransformation of such a heterodyne block diagram will be insufficientlyhigh ones than in case of using a heterodyne harmonic mixer. Advantagesof such a circuit diagram consist in that there is a significantsimplification of the receiving-amplification channel, since theheterodyne signals in a frequency range of up to several GHz may begenerated by means of conventional transistor oscillator, but its signalis fed to the heterodyning antenna element by means of coaxial cable orcorresponding band line with the integrated elements of amplifier unitand input receiving module decoupling. Besides, carrier frequencies ofthe doublet signal may be changed in anyone range (corresponding to arange of antenna operation frequencies, but there may be bands up to 200GHz and over, besides, such elements can be easy realized in S-MM range,and all it is determined by means of antenna an corresponding non-linearelement production technology, but the receiving blockblock diagram,including the heterodyne 356, can remain the same one.

The above-discussed block diagrams and approaches of encoding ofradiation, illuminating the object (by means of oscillators OMCS anddiscussed diffusers) undoubtedly do not limit a number of possibleapproaches for an encoding of such a radiation, which may be realized byany other alternative way (including the well-known ones, for example,only by means of distinctive amplitude modulation of radiation inchannels of corresponding partial sources of radiation and so on).

In FIG. 60 there is represented one of possible realizations oftransceiver 357, based on the usage of one of realizations of the OMCS102 of the doublet signals (see FIG. 51). In the description of thetransceiver functioning FIGS. 60, 51, 55 and 56 will be used. Thetransceiver is schematically represented, and the block diagram has beenchanged in accordance with its waveduide or planar monolithicrealization (taking into consideration the above-adduced understandingsabout possible realizations of the monolithic OMCS of MM range. The baseof receiver 358 of the transceiver 357 is the doublet oscillator 102 ofmutually-coherent signals, a functioning principle of which is abovedescribed in detail (see FIG. 51), and input/output points of the module102 correspond to the reference numbers of FIG. 51. An antenna system ofthe receiver is conditionally designated by means of unit 359 and canhave any realization of the antenna system (above-discussed in detail)for a radiation of the doublet signal, generated by the OMCS 102 (seeFIG. 60) into a free space (including also a monolithic realization ofthis unit). In FIG. 60 there are conditionally shown the outputs 258,259 of the unit 102 independent channels, through which thecorresponding doublet components are fed to an independent or unitedantenna (see above). The difference frequency of the doublet spectrallines is determined by the outer oscillator 98 in accordance with FIG.60 (which both may be stabilized one and changed one by frequency),besides it is essentially in order to frequencies of said oscillator 98and frequencies of message signal would be separated by frequency bymeans of corresponding receiving device 360 of the transceiver 357 (seebelow). The message signal source (for example, an output of sequentialcomputer port in the form of the port, operating for a transmission, orone of outputs of parallel port) is shown in the form of unit 278, asignal from which is fed to one of summing up device 277, and on itssecond input there is fed an error signal (of phase mismatch) from anoutput of the band filter 257 (see FIG. 51) through a contact terminal274 (besides, the cross connection 276 in the unit 102 should be removed(see FIG. 51)) the sum signal (its voltage equals to a sum of errorsignal voltage and voltage of message signal) through a contact terminal275 of the unit 102 is fed to the control electrode 101 of the VCO 60 inaccordance with FIG. 51. Besides, the frequency filter 254 of phase-lockloop of the unit 102 is selected in such a manner that the signal ofmessages is completely suppressed by said filter and is absent on theoutput of the amplifier 254 (see FIG. 51). Another possibility ofmodulation is the usage of the phase or amplitude modulator 63 (see FIG.51)—in this case the source 278 of messages is connected to themodulator 63 for its control (the cross connection 276 is switched on,the modulator 62 is absent one (see FIG. 51), and conditions on thebands of the filters 95, 253 are the same ones as those, that areabove-mentioned).

A receiving part 360 of the transceiver 357 also uses units, functioningof which was early analyzed. The doublet signals received by means ofreceiving antenna 321, are amplified by means of typical radio technicalunit 351 of amplification and heterodyning (see FIG. 60) (possibleconstructions of which were above-discussed in connection with FIGS. 56and 57). Besides, a signal of heterodyne 361 (see FIG. 59) is fed to theheterodyne input 326 of the mixer 325 (see FIG. 56), being a part of theunit 351. The doublet signals, which are shifted with respect to afrequency of the heterodyne 361 and are amplified ones, are fed to aninput of the square-law detector 362, wherein the correspondingdifference signal is separated from it. By means of filters 362 and 363from the difference signals there are separated spectral components,corresponding to an informational signal 362 and correspondingly topreferably discrete component 363 (which is determined by means ofselective mode of modulation of the doublet line in the receiver 358 andwhich has a frequency or frequency band of the difference frequencyoscillator 98). The signal spectral components are fed from an output ofa filter 361 to an input of the amplifier-parametric transformer 327,describe in connection with FIG. 56. On a heterodyne input 364 of theunit 327 (see FIG. 60) (being an input of a frequency shifter 333, beinga part of the unit 327 (see FIG. 55)) there is fed a signal of secondheterodyne 365 of the VCO, operating in the range of the differencesignal from an output of a power divider 366, an output of which isconnected to an input of the second heterodyne 365. Another portion ofthe signal power of this second heterodyne 365 through another arm ofthe power divider 366 is fed to one of inputs of a mixer 367. On anotherinput of the mixer 367 there is fed a synchronizing component of inputsignal, which is separated by means of filter 363 and which has afrequency, that is equivalent with respect to the the frequency ofsignal of the oscillator 98 in block diagram of the receiver 358. For animprovement of synchronization (if necessary) the message signal 278(see FIG. 60) may be periodically switched off, providing with a passageon the output of the receiver only a synchronization signal (a signal ofnon-modulated difference frequency). The signal of the phase mismatchbetween the synchronizing signal and the signal of the second heterodyne365, from the mixer 367 output through a filter 368 is fed to theelectrode of the VCO 365 for reducing said phase mismatch to zero andfor provision with a phase synchronism of the VCO signals and thesynchronization signal. The controlled phase shifter 333 in acomposition of the unit 327 may provide with an automatic selection ofoptimal phase shift of the VCO 365 signal before a feeding of the signalto the heterodyne input of the mixer 326. A resultant signal from anoutput 369 of the unit 327 (coinciding with an output of the band filter334 (see FIG. 55) is fed to an input of demodulator 370, which is eitheran amplitude demodulator (amplitude detector), if it was realized theamplitude modulation of the difference signal by means of thedemodulator 63 (see FIG. 51), or a frequency/phase demodulator, if itwas realized a frequency/phase modulation of the difference signal inthe transmitter 358 (or by means of modulator 63 in accordance with FIG.51 or by means of switching on of the elements 277, 278 in accordancewith FIG. 51). From an output of the corresponding demodulator a signalthrough a filter 371 is fed to a message receiver (for example,receiving port of computer) 372.

It is naturally that the transmitting antenna 359 and the receivingantenna 321 should be electro-dynamically uncoupled for providing with aminimal infiltration of input signal of the transmitter 359 into thereceiving antenna 327 (it is easy technically realizable in MM rangeincluding the usage of absorbing materials). It is also understood thata frequency of the frequency-stabilized signal of the referenceoscillator 98 and pass bands of the band filters 361 an 362 of thereceiver, being a part of the same transceiver 357, should not coincide.

Advantages of such a transmitter consist in a simplicity of constructiveand technological realization of both the receiver 360 and transmitter(in case of monolithic embodiment such a transmitter is simple,inexpensive an may operate in anyone band at least of MM range). Owingto a frequency stability of the difference signal of the filters 362,363 (see FIG. 60) and filters 332, 334 (see FIG. 55) may be exactlytuned to the band of corresponding signals, providing with a strongrejection of noises and interferences as well as providing with aspectral concentration of informational channels. A broadening of bandof the modulation signals is provided by means of arbitrary selection ofpractically anyone frequency of the difference signal, but a broadeningof band of carrier frequencies is provided by means of selection of onlyresonance antennae of transmitter oscillators (for example, in theintegral embodiment). The transceiver may be intended for a concealedcommunication, if frequencies of MM oscillator are arbitrary changedupon a transmission of the corresponding signals for a tuning ofparameters of the transceiver modules, if it is necessary.

The usage of the aforesaid OMCS generators used in tranceiving(illuminating/receiving) systems of MMW/SMMW imaging systems, in whichthe master oscillator like 280 (see FIGS. 52 to 54) is used asheterodyne local oscillator of downconverted mixer like 326 (see FIG.55) of the receiving device of the imaging system, but the followeroscillators of the OMCS generator like 59 and 60 being phase-locked onthe master oscillator 280 are used for an illumination of diffuser ofanyone type and then for illumination of inspection scene, allows toachieve an extremely high spectral concentration of generated frequencydifference beat signals, carrying image (or communication) information.In FIG. 61 to illustrate of aforesaid there is shown a spectrum of thefrequency difference beat signal, arising on the output of said mixer326 (see FIG. 55). Spectrum component like 373 and all the distinctcomponents of side band like 210 (see FIG. 61) will be stably located atthe spectral axis ω (wherein ω is a frequency of frequency differencebeat signal) with accuracy which is equal to bandwidth of referencesignal of said quartz stabilized reference oscillator like 98 discussedin connection with FIGS. 51-55. It means that spectral stability of saidfrequency difference beat signal components may achieve value in 1 Hzand better (in case of usage quartz and thermo stabilization) which willbe conserved for a long time. In imaging system in which At that sideband 210 in FIG. 61 consists from spectral lines like 211,212 discussedin connection of FIG. 41 (which appear when the encoding diffuser 111shown in FIG. 19 is illuminated with signal of phase locked oscillatorlike 59 or 69 (directly or after its frequency multiplication and) anddown converted mixer is pumped by signal of the master oscillator like280) but being down-converted at frequency of reference oscillator 98.Let us present that amount of diffuser independent cells (elements)independently modulating radiation scattered is nearly 1000 cells andimage frame update rate of imaging system is 10 Hz then total bandwidthof correspondent frequency difference beat signals will not exceed 10KHz. At that said narrow band will contain independent information on1000 independent angles of incidence of illumination radiation onobserved object. Frequency of said reference oscillator 98 may be equalΔω=1 GHz (that is coincident with average-central frequency 374 in FIG.61 of discussed frequency difference beat signals) and even more. Itmeans that receiving channel may be designed to provide sharp selectionof information signals amongst all signals received by the receivingdevice of imaging system and provide extremely high dynamic range foritself and concurrently provide extremely low level of power ofradiation required for illuminating an observable object. From anotherside aforesaid approach provides high density frequency multiplexing ofinformation in radiation scattered by the observable object taking intoaccount that frequency of correspondent reference oscillators of saidOMCS generator are chosen carefully and closely pitched to provide suchmultiplexing.

If imaging system is based on usage of a diffuser which is capable onlyto destroy a spatial coherence of scattered radiation without itsencoding, then widening of bandwidth of spectral line ofdiffuser-illuminating radiation will not exceed value in tens of Hz andwidened spectral line after its downconversion into said frequencydifference beat signal spectral range will be stable as discussedearlier. If 10 independent frequency distinct radiation beams willilluminate spatially distinct portion of the diffuser to create 10independent partial image as discussed above in connection of FIGS. 30,33, 34 then total information band of frequency difference beat signalsproduced in every receiving channel of receiving device of the imagingsystem will not exceed 100-1000 Hz. While for example all images shownin FIGS. 46-48 will be obtained simultaneously It is obvious that forillumination system it may be used radiation beams with differentcarrier frequency, different polarization beams and so on. Simultaneoususage of such beams for illumination and receiving correspondentindependent partial image will increase aforesaid narrow bandwidth ofcorrespondent frequency difference beat signal only by a factor of 10 to100.

In FIG. 62 there is represented a characteristic distribution ofspectrum of frequency difference beat signals, formed on an output ofthe mixer 326, when neighbor frequencies of the phase-locked oscillatorslike 59, 60 of the OMCS generator from FIG. 51-53 are differ one fromanother not more than possible widening of correspondent frequencydifference beat signals produced by mixing received signals with signalof the master oscillator 280 as discussed above multiply. For example ifradiation beam illuminates radiation-encoding diffuser with number ofcells less than 1000 than widening of correspondent frequency differencebeat signal will not exceed value in several tens of KHz (see line 374in FIG. 62) if another beam illuminates spatial coherence-destroyingdiffuser as discussed above in connection with FIG. 61 then bandwidth ofcorrespondent frequency different beat signal will not exceed severaltens of Hz and so on. Owing to a high stability of the spectrum offrequency difference beat signals a distribution of the completespectrum (see FIG. 62) will be tightly pitched and each independentcomponent of this spectral distribution (carrying own individualinformation about an object) may be with a high accuracy identified andmeasure in a corresponding signal-processing unit (see the units 337 and349 in FIG. 55). Besides, in each other receiving channel of thereceiving device, electrically connected to correspondent receivingelement like 47 of the array 46 (see FIG. 35), on output ofcorrespondent square-law detector like 326 (see FIG. 55) or detector 352(see FIGS. 56 to 59) producing frequency difference beat signals willappear own spectrum distribution like shown in FIG. 62 but carrying aninformation about another surface portion (or another internalstructure) 187 of the object 9, on which this element 47 of thereceiving array 46 (see FIG. 35) “looks” by means of the focusing lens14. Each multi-parametric pixel of the obtained multi-parametric imagewill have great volume of information, which can be presented in theform of corresponding diagrams of arrays like 216, 217, being only apart of whole set 214 of such diagrams as discussed above in connectionof FIG. 45. Besides, it is understood that such informationarrays-diagrams may be obtained almost instantly in very short framerate (up to several milliseconds and less depending on design of imagingsystem). There are no real physical reason to limit this rate exceptingimaging system design peculiarities. From another side the sameinformation array-diagrams can be obtained in sequence of time totallyor partially when all or only part of changeable physical parameters ofilluminating radiation swept in time.

In any case the proposed methods of generating andtransmitting/receiving of radiation for active imaging and correspondentimaging system transceiver systems allow to attain a great densityfrequency multiplexing of information on observable object contained inradiation being transmitted forward and scattered from the object. Itallow to essentially reduce level of power of object-illuminatingradiation (really uo to level of natural radiation emitted in sceneswith environmental), essentially to emhance quality of formed image andreveal novel possibilities in their processing.

If it is necessary to obtain an additional information, the usage ofOMCS and a specialized unit in a composition of receiving device,separating various difference signals in accordance with the correlation(2), there is a possibility to obtain various multiplicative images irtheir mixture in accordance with the correlation (20), which may carryan additional distinctive information about an object. Such variousmultiplicative images are formally described by the correlation (20), ifvarious indexes, characterizing different physical properties of partialradiations, correspond to different factors of the product in thecorrelation (20). For example, there may be various values of ((i,j) fora formation of product of partial images, formed by means of differentelements of diffuser (it is equivalent to the usage of decoding unit,separating products of said type), by means of changing a^(d) _(l) theabove-described two-frequency multiplicative images there may beobtained (it may be obtained the same ones if necessary or for variouspolarizations) multipliers of the product (20) and so on.

Before there were discussed the possibilities of the obtainment of thetwo-frequency multiplicative images in accordance with FIG. 9, when onthe output of the non-linear detector (diode) it may be obtained andseparated by means of filtration the signals, which are proportional toa product of signals and which belong to beams of various frequencies,simultaneously illuminating an object. For an obtainment of thetwo-frequency images with essentially distinctive frequencies it isrequired sufficiently complex realization of the receiving device.

However, for an obtainment of the mixture of the multiplicative images,components of which are formed by means of partial components ofradiation, reflected by various elements of encoding diffuser, there arenot required additional hardware means in comparison with earlydescribed ones.

Corresponding signals may be obtained upon an illumination of theradiation-encoding diffuser of imaging system by means of the doubletsignal radiation and then be generating correspondent frequencydifference beat signal by correspondent square-law detector incorrespondent receiver channel as multiply discussed above for examplein connection with FIG. 56-58. Such square-law detectors can be disposedas final stage of direct amplification and detection circuits incorrespondent receiving channels of MMW imaging camera (or example asdesigned by TRW) A spectrum of the difference frequency beat signal onthe output of the element 352 (see FIG. 58) is represented in FIG. 63.

It consists of several characteristic spectrally distinctive groups,formed upon a non-linear transformation of spectra of the doubletcomponents, extended into additional inter-modulation side bands afterreflection of doublet component radiation by radiation-encodingradiation. Side bands 377 and 378 are structurally identical to theabove-discussed informational frequency bands of 210 type in FIG. 61 orin FIG. 41, in which each component responds to a radiation, dispersedby means of distinct diffuser cell (element). They should be processedby means of the above-described methods.

Additional spectral distributions 379, 381, 380 are additive mixtures(sums) of spectral components, responding to the multiplicative images,formed by a product of components, dispersed by different cells(elements) of the diffuser. Each such a component is described by meansof relationship of type:

-   -   (22)

wherein ω_(i1,j1),ω_(i2,j2) are frequencies of modulation of thediffuser elements with indexes (i1,j1) and (i2,j2) in a matrixrepresentation of the diffuser elements; ^(α) ^(l) ^(d) {circumflex over(V)}_(i1,j1) ¹·u,·^(α) ^(l) ^(d) {circumflex over (V)}_(i2,j2) ² areamplitudes of phasors, responding to these elements of the diffuser (itis seen that in a signal they enter multiplicatively). From (22) it isclear that a spectral line 382 (see FIG. 63), which is distant from apoint on a spectral axis 383 (corresponding to a difference frequency ofprimordial doublet components) by a certain frequency step 4Δw_(i,j)will be a sum of components of the correlation (22) for differentelements of the diffuser (i1,j1) and (i2,j2), for which there is right acondition 4^(Δω) ^(i,j) ^(=ω) ^(i1,j1) ^(−ω) ^(i2,j2) . In FIG. 64 thereare shown three pairs of such elements of the diffuser 384, 385; 386,387; 388, 389, positioned in various points of the diffuser. For aspectrum component, shifted by a value, that is more than 4□w_(i,j),there will be other pairs of the diffuser elements, which are spatiallyshifted with respect to one another by a proportional distance (it issupposed that frequencies of modulation signals of the adjacent elementsdiffer by the same spatial step and build up on a line). It relatesanyone component of the band 383. The bands 381 and 380 also correspondto mixtures of multiplicative images for other shifts with respect tothe modulation frequencies. It is clear, that if at least one ofelements creates a mirror component and correspondingly a great value ofcorresponding phasor, in the mixtures there will dominate components ofproduct of the phasor of this element and of the phasors of thoseelements, which are shifted with respect to this element by a certainspectral step (or it is the same one in whole they are at anycharacteristic distance on the diffuser of this element).

Thus, the distribution 383 in FIG. 63 has a considerably smaller rangeof variations of the spectral components and lays less rigidrequirements to a dynamical range of receiving equipment and at the sametime allows to obtain partial images of different spatial statistics,but well then their accumulation in accordance with the above-describedprocedures will give the resultant image of improved quality.

It is known that the focusing elements, based on a diffraction principle(for example, zone Fresnel's lenses) change the their focal distanceupon the backlighting frequency variation. It allows to change a planeof harsh image by electronic rapid way without a spatial movement of anyelements of imaging system. However, such an approach was not used inpractice, since the corresponding oscillators radiate a spatiallycoherent radiation, and the obtained images has been turned out of theextremely low quality with a high level of coherent noises. The offeredapproach upon to a preliminary destruction (or encoding of spatialcomponents) of the spatial coherence by means of diffuser allows inpractice to use such focusing elements. Owing to this it may be builtthe three-dimensional image of high visual quality by means of scanningof article plane of zoned lens by depth of the observation zone in realscale of time and only by means of electronic control of frequency ofthe corresponding source of radiation. (There may be simultaneously orsequentially different three-dimensional cuts off at different distancesby depth of scene, if it is used a set of sources with fixed butdistinctive frequencies). A corresponding block-diagram is representedin FIG. 65. From the above-discussed block diagrams it differ only bytype of lens 390 in an imaging system, which in this block diagram is azoned Fresnel's lens, for which the position of the article plane (theplane, in which there are those article portions, which will be hashlyfocused on the receiving array) is changed. The position of the articleplane 391,392, 393 will be changed along an optical axis of the lens 390depending on a radiation frequency of the sources 3, 4, 5, illuminatingthe diffuser 7, besides, it may be the encoding diffuser 111 (see FIG.19) or the diffuser 159 (see FIG. 30 or FIG. 34), which only destructs aspatial coherence, but different portions of which are illuminated bymeans of differently encoded sources preferably of swept radiation byfrequency.

It should be added that millimeter receivers of various types, includingthe receivers of the direct amplification and detection, may receive andtransform into the difference frequencies the doublet spectral lines,central frequencies of which for the different doublet spectral linesmay essentially differ by from several MGz up to 1 GHz and even by 30 to40 GHz and may be located in anyone point of the spectrum, however, iftheir difference frequencies are put in good order an output of thecorresponding non-linear detector, bands of the corresponding differencefrequencies, put in good order and clearly spectrally localized, will beformed in the form of bands, which are convenient for their processingby means of corresponding hardware means of the receiving device 16.

An attractiveness of the offered approach consists in possibility ofusing of radiation of any type for an illumination of objects, if adiffuser is worked out for such a radiation dispersing (it concerns notonly a polarization, but also a radiation carrier frequency, besides,this frequency may not be limited by MMW/SMMW ranges, but it may layeven in the infrared and optical ranges—it is determined by means oftechnological capabilities of working out of dispersing elements for thediffuser in the mentioned ranges). For the MMW/SMMW range, for example,the linearly polarized radiation may be decomposed into a spatialcomponents by means of diffuser by the above-discussed way (or thediffuser has destructed the spatial coherence of the illuminatingradiation), besides, the imaging system may be provided with apolarization grid, which is preferably polarized in a plane, which isperpendicular with respect to the illuminating radiation. In this caseonly the radiation components, the polarization state of which ischanged after an interaction with an object, will be obtained by theimaging system receiving device. Drugs as well as a plastic weapon andexplosive are capable to change a polarization of the reflectedradiation, and they may be imaged by the offered system with a highcontrast and great number of details. Besides, such objects may beinvisible on the images, obtained in a co-polarized radiation. On thecontrary, an ordinary (metallic) weapon may have a bad contrast incross-polarized images. Since all the information, contained in theimages (including the co- and cross-polarized images) may be obtained atthe same time, the resultant images may be obtained in scale of realtime with the included co- and cross-polarized images into one such animage. In this case both the traditional weapon and the plastic weaponand drugs may be imaged with an improved quality and may be easyidentified. So, some more essential additional advantage is contained inthe offered active imaging system in comparison with any alternativesystems, including the passive imaging systems.

Upon the receiving by means of receiving equipment of the imagingsystema radiation spectrum, multiply splitted (decomposed) with respectto radiation features of splitted components of radiation, dispersedfurther by observed object, the radiation components, dispersed byvarious ways by different portions of the object, are separatelyidentified and isolated in each pixel of the received image. It allowsto control all the set of information about the object.

It is necessary to underline two essential moments of the offeredimaging technique.

Firstly, owing to the usage of artificial narrow-band MMW/SMMW modulatedradiation and specially worked out receiving equipment a level ofradiation, illuminating an object, will be below a level of radiation,radiated by natural way by human body in the MMW/SMMW range. So, anyoneperson, standing near a person being under the imaging systemobservation, will in whole radiate a MMW/SMMW power in the side of thisobserved person more than a corresponding system of the illumination ofthe used IMAGING SYSTEM.

Secondly, the receiving equipment of the offered system may be workedout in such a manner that such a system will be capable to form alongwith the active radiometric images as well as passive radiometric imageslike any passive systems, early worked out. It will take a place owingto that fact, that the first base cascades of the offered system ofblocks for transformation and amplification of the signals correspond tothe corresponding cascades of the passive imaging system. An elicitationof the signals belonging to the different partial images, will becarried out by means of additional frequency-selective circuits. Thus,the offered system will be capable to obtain passive images in thoserare cases, when such an information may be useful for aims ofdiscerning of concealed objects. The illumination system should bepreferably switched off during a time of formation of the passiveimages, since active signals may influence on signals of the passiveimages.

The offered imaging system will obtain scopes of information, which arenot attainable for any other imaging system, detecting a contraband ofsystems, including, certainly, also passive radiometric IMAGING SYSTEM.On the other hand, for a realization of such systems it is not necessaryan additional development of the technology level of the MMW/SMMWcomponents and components, and such systems can be effectively workedout on the base of already worked out technology. Additional diffuserand equipment for controlling of procedures of imaging and processing ofimages are not expensive ones in comparison with modules of the passivesystem. Advantages, which are open upon the usage of such systems, areobvious ones.

INDUSTRIAL APPLICABILITY

The present invention is industrially applicable one, since it is basedon the usage of the known technologies of electronic equipmentproduction and does not require an additional and special equipmentsexcept those, which are used in production of electronic and computerapparatuses.

1. A system for millimeter and sub-millimeter wave imaging, comprisingat least one source of millimeter or sub-millimeter wave radiation beingdesigned in the form of a set of separate independent radiationelements, wherein constituent radiation emitted by each said radiationelement of said set of the radiation elements is characterized by all ora part of its radiation physical features, which are different in valuefrom correspondent radiation physical features of constituent radiationemitted by any other radiation element of said set of the radiationelements, means for focusing radiation of said source, which ispreviously scattered with an observable object, onto receiving means,designed with capabilities of independent receiving of differentportions of the radiation focused thereon, each of which is scatteredwith a particular spatial portion of the observable object and/orinspection area, being located in a field of view of said means offocusing, and with capabilities to transform said portions of thefocused radiation into a correspondent matrix set of electrical signals,receiving means, outputs of which are connected to processing meansbeing intended for generating an correspondent matrix image of theobservable object and/or the inspection area from said matrix set of theelectrical signals and for further displaying said generated matriximage, therewith each pixel of said matrix image corresponds to aparticular electrical signal being generated by the receiving means froma particular portion of the radiation scattered with a correspondentparticular spatially-determined portion of the observable object and/orthe inspection area and further correspondingly focused on the receivingmeans by said means of focusing, characterized in that it is providedwith a diffuser, disposed at a distance from said radiation source andintended to be illuminated with the radiation of said source and furtherto scatter the incident radiation towards the inspection area, whereinthe diffuser is designed with capabilities to diffusely scatter incidentradiation with spatially-different portions of the diffuser each ofwhich provides additional distinct encoding of originated scatteredradiation component, due to distinct modulation of scatteringcharacteristics of each of said diffuser portions and with a capabilityto reduce spatial coherence of diffuser-scattered radiation, in that thesaid independent radiation elements each of which is designed withcapabilities to emit constituent radiation exhibiting either a fixed ortime-varied in value said radiation physical features, in that thereceiving means is designed with a capability of independent receivingof each encoded radiation component in all the ranges of the variationof values of the physical features of the radiation, incident from theinspection area, i.e. with a capability of time demultiplexing of saidcorrespondent electrical signals, and with a capability of convertingeach said electrical signal from said matrix set of the electricalsignals, by usage of decoding, to an additional set of secondaryelectrical signals, each of secondary electrical signals of the samesaid additional set to a particular distinctively encoded radiationcomponent focused either belonging to a single diffuser-originated setof distinctively encoded correspondent radiation components which isoriginated from the radiation of said source exhibiting a single set ofthe same correspondent values of the correspondent said radiationfeatures of said source radiation or belonging to one of suchdiffuser-originated sets each of which is originated from the radiationof said source exhibiting a particular set of the same correspondentvalues of the correspondent said radiation features of said sourceradiation if said source includes at least one said independentradiation element emitted constituent radiation exhibiting time-variedin value said radiation physical features, therewith each of saiddistinctively encoded radiation components is focused onto the receivingmeans from the same particular spatial portion of the observable objectand/or the inspection area, each of which is distinctly received anddecoded at one or various instants during a total time of receiving bythe receiving means of the radiation components, reflected from, i.e.scattered with, all said correspondent spatial portions of theobservable object and/or the inspection area for a single set of thesame correspondent values of said radiation features of the radiation ofsaid source or for all possible correspondent such sets if said sourceincludes at least one said independent radiation element emittingconstituent radiation exhibiting time-varied in value said radiationphysical features provided that each of the correspondent time-variedphysical features takes on sufficiently different values, in that theprocessing means are designed with function of independent receiving ofsaid separate secondary electrical signals, with a function of theirarranging into partial matrix sets of said secondary electrical signalseach of which, being from the same said partial matrix set, correspondsto a particular distinctively encoded radiation component whichoriginated from the radiation of said source exhibiting the same set ofthe same correspondent values of the correspondent said radiationphysical features of said source radiation with a function of generatingof partial matrix images from correspondent constituent matrix sets ofthe electrical signals, and with a function of forming of a resultantimage of observable object and the inspection area by means of combiningsaid matrix partial images and/or their portions.
 2. A system as setforth in claim 1, characterized in that the processor is designed withfunctions of controlling elements of the encoding diffuser and with avariation of distribution of the encoding parameters significances withrespect to said portions of the diffuser according to a prescribedalgorithm.
 3. A system as set forth in claim 1, characterized in that aminimal resolution of the receiving device with respect to said encodingparameter is more tan a minimal difference between significances ofencoding parameters of the nearest encoded components of the radiation.4. A system for millimeter and sub-millimeter wave imaging, comprisingat least one source of millimeter or sub-millimeter wave radiation beingdesigned in the form of a set of separate independent radiationelements, wherein constituent radiation emitted by each said radiationelement of said set of the radiation elements is characterized by all ora part of its radiation physical features, which are different in valuefrom correspondent radiation physical features of constituent radiationemitted by any other radiation element of said set of the radiationelements, means for focusing radiation of said source, which ispreviously scattered with an observable object, onto receiving means,designed with capabilities of independent receiving of differentportions of the radiation focused thereon, each of which is scatteredwith a particular spatial portion of the observable object and/orinspection area, being located in a field of view of said means offocusing, and with capabilities to transform said portions of thefocused radiation into a correspondent matrix set of electrical signals,receiving means, outputs of which are connected to processing meansbeing intended for generating an correspondent matrix image of theobservable object and/or the inspection area from said matrix set of theelectrical signals and for further displaying said generated matriximage, therewith each pixel of said matrix image corresponds to aparticular electrical signal being generated by the receiving means froma particular portion of the radiation scattered with a correspondentparticular spatially-determined portion of the observable object and/orthe inspection area and further correspondingly focused on the receivingmeans by said means of focusing, characterized in that it is providedwith a diffuser, disposed at a distance from said radiation source andintended to be illuminated with the radiation of said source and furtherto scatter the incident radiation towards the inspection area, whereinthe diffuser is designed with capabilities to diffusely scatter incidentradiation or the diffuser is designed with capabilities to diffuselyscatter incident radiation with spatially-different portions of thediffuser each of which provides additional distinct encoding oforiginated scattered radiation component, due to distinct modulation ofscattering characteristics of each of said diffuser portions and/or witha capability to reduce spatial coherence of diffuser-scatteredradiation, in that the said independent radiation elements each of whichis designed with capabilities to emit constituent radiation exhibitingeither a fixed or time-varied in value said radiation physical features,wherein each separate independent radiation element of the radiationsource is designed with a capability of encoding of said emittedconstituent radiation, including also a capability of its modulation,which is different with respect to encoding of the radiation of otherseparate independent radiation elements, in that the receiving means isdesigned with a capability of independent receiving of each encodedradiation component in all the ranges of the variation of values of thephysical features of the radiation, incident from the inspection area,i.e. with a capability of time demultiplexing of said correspondentelectrical signals, and with a capability of converting each saidelectrical signal from said matrix set of the electrical signals, byusage of decoding, to an additional set of secondary electrical signals,each of secondary electrical signals of the same said additional set toa particular distinctively encoded radiation component focused eitherbelonging to a single diffuser-originated set of distinctively encodedcorrespondent radiation components which is originated from theradiation of said source exhibiting a single set of the samecorrespondent values or closely the same correspondent values of thecorrespondent said radiation features of said source radiation orbelonging to one of such diffuser-originated sets each of which isoriginated from the radiation of said source exhibiting a particular setof the same correspondent values or closely the same correspondentvalues of the correspondent said radiation features of said sourceradiation if said source includes at least one said independentradiation element emitted constituent radiation exhibiting time-variedin value said radiation physical features, therewith each of saiddistinctively encoded radiation components is focused onto the receivingmeans from the same particular spatial portion of the observable objectand/or the inspection area, each of which is distinctly received anddecoded at one or various instants during a total time of receiving bythe receiving means of the radiation components, reflected from, i.e.scattered with, all said correspondent spatial portions of theobservable object and/or the inspection area for a single set of thesame correspondent values or closely the same correspondent values ofthe radiation of said source or for all possible correspondent such setsif said source includes at least one said independent radiation elementemitting constituent radiation exhibiting time-varied in value saidradiation physical features provided that each of the correspondenttime-varied physical features takes on sufficiently different values, inthat the processing means are designed with function of independentreceiving of said separate secondary electrical signals, with a functionof their arranging into partial matrix sets of said secondary electricalsignals each of which, being from the same said partial matrix set,corresponds to a particular distinctively encoded radiation componentwhich originated from the radiation of said source exhibiting the sameset of the same correspondent values or closely the same correspondentvalues of the correspondent said radiation physical features of saidsource radiation with a function of generating of partial matrix imagesfrom correspondent constituent matrix sets of the electrical signals,and with a function of forming of a resultant image of observable objectand the inspection area by means of combining said matrix partial imagesor their portions.
 5. A system as set forth in claim 4, characterized inthat distinctive and/or scanned physical parameters of the radiations ofsaid independent elements of radiations are spatial directions ofpropagation of beams of these radiations such that said diffuserportions, which are spatially distinctive ones and are illuminated bythese radiations, correspond to the various distinctive directions ofpropagation of the correspondent radiations.
 6. A system as set forth inclaim 4, characterized in that the diffuser is additionally providedwith polarization means, separated from the radiation, reflected by thediffuser, a radiation, which is preferably linear-polarized in the firstspatial direction, but the receiving device is provided withpolarization means for a separation from the radiation, received by it,a radiation, which is linear-polarized in the second spatial direction.7. A system as set forth in claim 6, characterized in that said firstdirection coincides with said second direction.
 8. A system as set forthin claim 6, characterized in that said first direction is orthogonal onewith respect to said second direction.
 9. A system as set forth in claim4, characterized in that each independent element is provide with anadjustable attenuator, controlled by said processor, for permissibledecreasing of an average level of power of the electrical signals of thecorrespondent partial image.
 10. A system as set forth in claim 4,characterized in that a radiation frequency is represented bydistinctive and/or scanned physical parameters of the radiations of saidindependent elements of radiations.
 11. A system for millimeter andsub-millimeter wave imaging, comprising at least one source ofmillimeter or sub-millimeter wave radiation, means for focusingradiation of said source, which is previously scattered with anobservable object, onto receiving means, designed with capabilities ofindependent receiving of different portions of the radiation focusedthereon, each of which is scattered with a particular spatial portion ofthe observable object and/or inspection area, being located in a fieldof view of said means of focusing, and with capabilities to transformsaid portions of the focused radiation into a correspondent matrix setof electrical signals, receiving means, outputs of which are connectedto processing means being intended for generating an correspondentmatrix image of the observable object and/or the inspection area fromsaid matrix set of the electrical signals and for further displayingsaid generated matrix image, therewith each pixel of said matrix imagecorresponds to a particular electrical signal being generated by thereceiving means from a particular portion of the radiation scatteredwith a correspondent particular spatially-determined portion of theobservable object and/or the inspection area and further correspondinglyfocused on the receiving means by said means of focusing, characterizedin that it is provided with a diffuser, disposed at a distance from saidradiation source and intended to be illuminated with the radiation ofsaid source and further to scatter the incident radiation towards theinspection area, wherein the diffuser is designed with capabilities todiffusely scatter incident radiation with spatially-different portionsof the diffuser each of which provides additional distinct encoding oforiginated scattered radiation component, due to distinct modulation ofscattering characteristics of each of said diffuser portions and with acapability to reduce spatial coherence of diffuser-scattered radiation,in that the radiation source is designed with all or part of radiationphysical features of emitted radiation, which are fixed or time variedin value, in that the receiving means is designed with a capability ofindependent receiving of each encoded radiation component in all theranges of the variation of values of the physical features of theradiation, incident from the inspection area, i.e. with a capability oftime demultiplexing of said correspondent electrical signals, and with acapability of converting each said electrical signal from said matrixset of the electrical signals, by usage of decoding, to an additionalset of secondary electrical signals, each of secondary electricalsignals of the same said additional set corresponds to a particulardistinctively encoded radiation component focused either belonging to asingle diffuser-originated set of distinctively encoded correspondentradiation components which is originated from the radiation of saidsource exhibiting a single set of the same correspondent values of thecorrespondent said radiation features of said source radiation orbelonging to one of such diffuser-originated sets each of which isoriginated from the radiation of said source exhibiting a particular setof the same correspondent values of the correspondent said radiationfeatures of said source radiation if said source includes at least onesaid independent radiation element emitted constituent radiationexhibiting time-varied in value said radiation physical features,therewith each of said distinctively encoded radiation components isfocused onto the receiving means from the same particular spatialportion of the observable object and/or the inspection area, each ofwhich is distinctly received and decoded at one or variousinstants-during a total time of receiving by the receiving means of theradiation components, reflected from, i.e. scattered with, all saidcorrespondent spatial portions of the observable object and/or theinspection area for a single set of the same correspondent values ofsaid radiation features of the radiation of said source or for allpossible correspondent such sets if said source includes at least onesaid independent radiation element emitting constituent radiationexhibiting time-varied in value said radiation physical featuresprovided that each of the correspondent time-varied physical featurestakes on sufficiently different values, in that the processing means aredesigned with function of independent receiving of said separatesecondary electrical signals, with a function of their arranging intopartial matrix sets of said secondary electrical signals each of which,being from the same said partial matrix set, corresponds to a particulardistinctively encoded radiation component which originated from theradiation of said source exhibiting the same set of the samecorrespondent values of the correspondent said radiation physicalfeatures of said source radiation with a function of generating ofpartial matrix images from correspondent constituent matrix sets of theelectrical signals, and with a function of forming of a resultant imageof observable object and the inspection area by means of combining saidmatrix partial images or their portions.
 12. A system as set forth inclaim 11, characterized in that the processor is designed with functionsof controlling elements of the encoding diffuser and with a variation ofdistribution of the encoding parameter significances with respect tosaid portions of the diffuser according to an algorithm, prescribed bythe processor.
 13. A system as set forth in claim 11, characterized inthat a minimal resolution of the receiving device with respect to saidencoding parameter is more tan a minimal difference betweensignificances of encoding parameters of the nearest encoded componentsof the radiation.
 14. A system as set forth in claim 11, characterizedin that a radiation frequency is a changed physical parameter of theradiation source.
 15. A system for millimeter and sub-millimeter waveimaging, comprising at least one source of millimeter or sub-millimeterwave radiation, means for focusing radiation of said source, which ispreviously scattered with an observable object, onto receiving means,designed with capabilities of independent receiving of differentportions of the radiation focused thereon, each of which is scatteredwith a particular spatial portion of the observable object and/orinspection area, being located in a field of view of said means offocusing, and with capabilities to transform said portions of thefocused radiation into a correspondent matrix set of electrical signals,receiving means, outputs of which are connected to processing meansbeing intended for generating an correspondent matrix image of theobservable object and/or the inspection area from said matrix set of theelectrical signals and for further displaying said generated matriximage, therewith each pixel of said matrix image corresponds to aparticular electrical signal being generated by the receiving means froma particular portion of the radiation scattered with a correspondentparticular spatially-determined portion of the observable object and/orthe inspection area and further correspondingly focused on the receivingmeans by said means of focusing, characterized in that it is providedwith a diffuser, disposed at a distance from said radiation source andintended to be illuminated with the radiation of said source and furtherto scatter the incident radiation towards the inspection area, whereinthe diffuser is designed a capability to reduce spatial coherence ofdiffuser-scattered radiation, in that the radiation source is designedwith at least one from its radiation physical features of emittedradiation, which is time varied in value, in that the receiving means isdesigned with a capability of independent receiving of each encodedradiation component in all the ranges of the variation of values of thephysical features of the radiation, incident from the inspection area,i.e. with a capability of time demultiplexing of said correspondentelectrical signals, and with a capability of converting each saidelectrical signal from said matrix set of the electrical signals to anadditional set of secondary electrical signals, each of secondaryelectrical signals of the same said additional set corresponds to aparticular radiation component focused exhibiting with at least oneparticular value of at least one of said radiation features of saidradiation source, therewith each of said radiation components is focusedonto the receiving means from the same particular spatial portion of theobservable object and/or the inspection area, each of which isdistinctly received at one or various instants during a total time ofreceiving by the receiving means of the radiation components, reflectedfrom, i.e. scattered with, all said correspondent spatial portions ofthe observable object and/or the inspection area for all possiblesufficiently different correspondent values of at least one of saidradiation features of the radiation of said source, in that theprocessing means are designed with function of independent receiving ofsaid separate secondary electrical signals, with a function of theirarranging into partial matrix sets of said secondary electrical signalswhich correspondent to radiation components exhibiting the same value orclosely the same values of at least one of physical radiation featuresof said source with a function of generating of partial matrix imagesfrom correspondent constituent matrix sets of the electrical signals,and with a function of forming of a resultant image of observable objectand the inspection area by means of combining said matrix partial imagesor their portions.
 16. A system as set forth in claim 15, characterizedin that a distinctive radiation physical parameter of the radiationsource is a direction of its propagation, a variation of which in timeleads to a sequential with respect to time illumination of variousspatial portions of said diffuser.
 17. A system as set forth in claim15, characterized in that a radiation frequency is a changed physicalparameter of the radiation source.
 18. A system for millimeter andsub-millimeter wave imaging, comprising at least one source ofmillimeter or sub-millimeter wave radiation being designed in the formof a set of separate independent radiation elements, wherein constituentradiation emitted by each said radiation element of said set of theradiation elements is characterized by all or a part of its radiationphysical features, which are different in value from correspondentradiation features of constituent radiation emitted by any otherradiation element of said set of the radiation elements, means forfocusing radiation of said source, which is previously scattered with anobservable object, onto receiving means, designed with capabilities ofindependent receiving of different portions of the radiation focusedthereon, each of which is scattered with a particular spatial portion ofthe observable object and/or inspection area, being located in a fieldof view of said means of focusing, and with capabilities to transformsaid portions of the focused radiation into a correspondent matrix setof electrical signals, receiving means, outputs of which are connectedto processing means being intended for generating an correspondentmatrix image of the observable object and/or the inspection area fromsaid matrix set of the electrical signals and for further displayingsaid generated matrix image, therewith each pixel of said matrix imagecorresponds to a particular electrical signal being generated by thereceiving means from a particular portion of the radiation scatteredwith a correspondent particular spatially-determined portion of theobservable object and/or the inspection area and further correspondinglyfocused on the receiving means by said means of focusing, characterizedin that it is provided with a diffuser, disposed at a distance from saidradiation source and intended to be illuminated with the radiation ofsaid source and further to scatter the incident radiation towards theinspection area, wherein the diffuser is designed with capabilities todiffusely scatter incident radiation or the diffuser is designed withcapabilities to diffusely scatter incident radiation withspatially-different portions of the diffuser each of which providesadditional distinct encoding of originated scattered radiationcomponent, due to distinct modulation of scattering characteristics ofeach of said diffuser portions and/or with a capability to reducespatial coherence of diffuser-scattered radiation, in that said meansfor focusing is designed to be dependent on radiation carrier frequencyfor which the focal distance of said means for focusing depends on thefocused radiation carrier frequency, in that the said independentradiation elements each of which is designed with capabilities to emitconstituent radiation either at fixed values of carrier frequencieswhich are sufficiently different from each other or time-varied in valueof frequencies which are swept within quite wide ranges, wherein eachseparate independent radiation element of the radiation source isdesigned with a capability of encoding of said emitted constituentradiation, including also a capability of its modulation, which isdifferent with respect to encoding of the radiation of other separateindependent radiation elements, in that the receiving means is designedwith a capability of independent receiving of each encoded radiationcomponent in all the ranges of the variation of values of the of theradiation, incident from the inspection area, i.e. with a capability oftime demultiplexing of said correspondent electrical signals, and with acapability of converting each said electrical signal from said matrixset of the electrical signals, by usage of decoding, to an additionalset of secondary electrical signals, each of secondary electricalsignals of the same said additional set to a particular distinctivelyencoded radiation component focused either belonging to a singlediffuser-originated set of distinctively encoded correspondent radiationcomponents which is originated from the radiation of said sourceexhibiting a single set of the same correspondent values or closely thesame correspondent values of the correspondent said radiation carrierfrequencies of said source radiation or belonging to one of suchdiffuser-originated sets each of which is originated from the radiationof said source exhibiting a particular set of the same correspondentvalues or closely the same correspondent values of the correspondentsaid radiation carrier frequencies of said source radiation if saidsource includes at least one said independent radiation element emittedconstituent radiation exhibiting time-varied in value said radiationcarrier frequencies, therewith each of said distinctively encodedradiation components is focused onto the receiving means from thecorrespondent spatial portion of the observable object and/or theinspection area, each of which is distinctly received and decoded at oneor various instants during a total time of receiving by the receivingmeans of the radiation components, reflected from, i.e. scattered with,all said correspondent spatial portions of the observable object and/orthe inspection area for a single set of the same correspondent values orclosely the same correspondent values of the radiation of said source orfor all possible correspondent such sets if said source includes atleast one said independent radiation element emitting constituentradiation exhibiting time-varied in value said radiation carrierfrequencies provided that each of the correspondent time-varied carrierfrequencies takes on sufficiently different values, in that theprocessing means are designed with function of independent receiving ofsaid separate secondary electrical signals, with a function of theirarranging into partial matrix sets of said secondary electrical signals,each of which, being from the same said partial matrix set, correspondsto a particular distinctively encoded radiation component whichoriginated from the radiation of said source exhibiting the same set ofthe same correspondent values or closely the same correspondent valuesof the correspondent said radiation carrier frequencies of said sourceradiation with a function of generating of partial matrix images fromcorrespondent constituent matrix sets of the electrical signals, andwith a function of forming of set of partial resultant images ofobservable object and the inspection area by means of combining saidmatrix partial images associated with radiation components with the sameand closely the same encoding, and with function of forming 3D image ofobservable object and the inspection area by correspondent spatialarranging frequency-dependent said partially resultant images.
 19. Asystem as set forth in claim 18, characterized in that a zone Fresnel'slens is a frequency-dependent element of focusing.
 20. A system as setforth in claim 18, characterized in that set of independent elements ofradiation includes at least two radiation sources with a frequency,varied in sufficiently wide limits, and each of which is intended for anillumination of spatially different portions of said diffusers.
 21. Atransceiver of imaging system for an obtainment of complete informationfrom a radiation, scattered by an observable object under conditions oflow level of power of radiation illuminating said object, comprising aMMW/SMMW range heterodyne receiver, intended for a receiving of theMMW/SMMW imaged radiation of said imaging system, a source of MMW/SMMWradiation, intended for an illumination of the object or a diffuser,which scatters the source radiation toward object, besides, theheterodyne receiver includes a receiving antenna, connected to a firstsub-harmonic mixer fed by a first radiation oscillator, fulfilling afunction of the local oscillator for said first sub-harmonic mixer, afirst band filter, connected to the first mixer for a separation ofintermediate difference frequency signal, a second mixer, a signal inputof which is connected to an output of the first band filter, andheterodyne input of which is fed by output signal of a first frequencymultiplier input of which is connected to output of said first radiationoscillator, a second band filter, an input of which is connected to anoutput of said second mixer, a high-frequency or low-frequency analyzerof signals, inputs of which are correspondingly connected through thesecond band filter to an output of said second mixer, and to an outputof said first frequency multiplier, means for signal processing anddisplaying, connected to an output of said analyzer, a source ofradiation consists of a second radiation oscillator, an output of whichis connected to an input of a second frequency multiplier, an output ofwhich is connected to a radiation transmitting antenna and includes aservocontrolling unit for servocontrolling of frequency of radiation ofsaid second radiation oscillator by frequency of radiation of the firstradiation oscillator by means of forming a frequency difference beatsignal of a signal of said first oscillator and a signal of said secondoscillator and providing phase locking said frequency difference beatsignal by reference signal of a first reference signal oscillator bymeans of varying said frequency of said second oscillator radiation, theoscillator of the reference signal is intended for an activating of theservocontrolling unit and for a generating of the phase reference signalfor said signal analyzer, but said first and said second frequencymultipliers and the first sub-harmonic mixer are designed with acapability of functioning at the same harmonic order.
 22. A transceiveras set forth in claim 21, characterized in that the signal analyzerrepresents by itself two analog-digital converters, realizing asynchronous digitizing of the signal from the output of the second bandfilter and the multiplied signal of the reference signal oscillator fromthe output of said first frequency multiplier, and a processor which hasa memory for loading digital files of said digitized signals and isdesigned with a capability of a computation of amplitude and phaseinformation of the signals, received by said heterodyning receiver. 23.A transceiver as set forth in claim 21, characterized in that theservocontrolling unit represents by itself a first directional coupler,connected to an output of the first oscillator and realizing a partitionof the first oscillator signal with respect to a power into a smallerand greater portions, a second directional coupler is connected to anoutput of the second oscillator and realizing a partition of the firstoscillator signal with respect to a power into a smaller and greaterportions, a mixer which has inputs which are intended for a receiving ofthe smaller portions of said first and second oscillators, the mixerrealizes generating a difference frequency signal out of said signalsfor a feeding of this difference signal via the band filter into oneinput of phase detector, another input of which is intended for areceiving a signal of said reference signal oscillator, but an errorsignal of the phase detector, which is a signal of phase mismatchbetween the difference frequency signal of the signals of said first andsecond oscillators and the signal of the reference frequency oscillator,is fed to a controlling electrode of the second oscillator for varyingthe frequency of signal of the second oscillator such that it leads todecreasing of said phase mismatch.
 24. A transceiver as set forth inclaim 21, characterized in that the heterodyne receiver is mounted on amechanically scanning device with a capability to receive of radiationof complete image, formed by a system of imaging by means of theheterodyne receiver scanning in a plane of focussed image of thissystem.
 25. A transceiver as set forth in claim 24, characterized inthat the heterodyne receiver is designed in the form of an array ofheterodyne receivers, disposed in such a manner that phase centers ofsaid antenna receivers of each heterodyne receivers coincide with aplane of focused image of imaging system, but each heterodyne receiveris provided with a directional coupler for a transmission a portion ofthe power of the second oscillator to a heterodyne input of thecorrespondent first mixer, but said second oscillator is a general onefor all the heterodyne receivers, each of which is designed with acapability to receive a portion of its power via the correspondentdirection coupler.
 26. A transceiver of system for imaging of MMW/SMMWimages for an obtainment of detail information about a radiation,scattered by the object, under conditions of low level of the objectillumination power, comprising a receiver based on direct amplificationand detection of received MMW/SMMW radiation, intended for a receivingof MMW/SMMW radiation images in said system for imaging, a source ofcomposite MMW/SMMW radiation, intended for an illumination of the objector diffuser, which disperses the source radiation toward the object,besides, the receiver for direct amplification and detection includes areceiving antenna, connected to an amplifier of high frequency, a signalof which is fed into a square-law detector, an analyzer of signal, aninput of which is connected via a filter to an output of said square-lawdetector, means for signal processing and displaying, connected to anoutput of the analyzer, a source of composite radiation, consisting of afirst radiation oscillator, connected to a first directional coupler anddividing the signal of the first oscillator with respect to a power ontoa greater and smaller portions, and of a second radiation oscillator,connected to a second directional coupler, dividing the signal of thesecond oscillator with respect to a power onto a greater and smallerportions, of output antenna system, intended for a transmission of saidgreater portions of power of signals of the first and second oscillatorsin a free space preferably by the same way, a servocontrolling unit, toinputs of which from the correspondent outputs of said directionalcouplers there are fed said signals of smaller power of correspondentlyfirst and second oscillators and which is intended for servocontrollingradiation frequency of the second radiation oscillator by frequency ofthe first radiation oscillator, and an oscillator of reference signal,intended for an activating of the servocontrolling unit and for agenerating of the reference signal for said signal analyzer.
 27. Atransceiver as set forth in claim 26, characterized in that saidanalyzer represents by itself a band filter with a central passfrequency, corresponding to a frequency of said oscillator of referencesignal, connected to an analog-digital convertyer, realizing digitalsamplings of signal and fillings by these samplings a memory ofprocessor, realizing a processing of these samplings in order to obtaina spectral composition of this signal.
 28. A transceiver as set forth inclaim 27, characterized in that said analyzer additionally consists ofmixer, a signal input of which is connected to an output of said bandfilter, but to a heterodyne input of said mixer there is fed by a signalof the reference signal oscillator, and an output signal of said mixervia the filter is fed to an input of the analog-digital converter,realizing digital samplings of signal and fillings by these samplingsthe memory of the processor, besides the processor realizes a digitalprocessing of these samplings in order to obtain a spectral compositionof this signal.
 29. A transceiver as set forth in claim 26,characterized in that the servocontrolling unit represents by itself amixer, inputs of which are intended for a receiving of the smallersignal portions of said first and second oscillators and are connectedto the correspondent outputs of said first and second directionalcouplers, and which realizes a separation of the difference frequencysignal out of said signals for feeding of this difference frequencysignal via the band filter to one input of the phase detector, anotherinput of which is intended for a receiving of signal of said referencesignal oscillator, but an error signal of the phase detector, which is asignal of phase mismatch between the difference frequency signal of thesignals of said first and second oscillators and the signal of thereference frequency oscillator, is fed to a controlling electrode of thesecond oscillator for varying the frequency of the second oscillatorsignal such that it provides a decrease of said phase mismatch.
 30. Atransceiver as set forth in claim 26, characterized in that the receiverfor the direct amplification and detection is mounted on a scanningdevice with a capability to receive of complete image radiation, formedby a system of imaging by means of the heterodyne receiver scanning in aplane of focused image of this system.
 31. A transceiver as set forth inclaim 26, characterized in that in a area of focusing of focusingelement of the imaging system there is positioned an array of saidreceivers for the direct amplification and detection in such a mannerthat receiving antennae of said receivers are positioned near to asurface of focused image of the focusing element.
 32. A transceiver asset forth in claim 27, characterized in that in it there is used a setof said composite radiation sources, besides, frequencies of signals ofthe reference signal oscillators of the correspondent sources differfrom each other, to an output of the square-law detector of the receiverfor the direct amplification and detection there are parallel connectedseveral said analyzers of signals, a number of which equals to a numberof said sources of composite radiation in said set, and a centralfrequency of the band filter of the correspondent analyzer equals to afrequency of signal of the reference oscillator of the correspondentsource of the composite radiation.
 33. A transceiver as set forth inclaim 27, characterized in that in it there is used the set of saidsources of composite radiation, besides, the frequencies of signals ofthe oscillator of the reference signals of the correspondent sourcesdiffer from each other, to an output of the square-law detector of thereceiver for the direct amplification and detection there are parallelconnected several said analyzers of signals, a number of which equals toa number of said sources of composite radiation in said set, and acentral frequency of the band filter of the correspondent analyzerequals to a frequency of signal of the back-up oscillator of thecorrespondent source of the composite radiation, besides to anheterodyne input of mixer of said signal analyzer there is fed a signalof reference oscillator of said source of the composite radiation.
 34. Atransceiver as set forth in claim 28, characterized in that varioussources of the composite radiation from the set of the sources areintended for an illumination of preferably spatially-different portionsof the object or diffuser.
 35. A transceiver as set forth in claim 28,characterized in that various sources of the composite radiation fromthe set of sources have essentially different their average frequencies,calculate as an arithmetic mean of frequencies of correspondent pairedoscillators.
 36. A transceiver as set forth in claim 26, characterizedin that a radiation of said greater portion of signal of the firstoscillator, propagating in a free space, is preferably linearlypolarized in a first spatial direction, but a radiation of said greaterportion of signal of the second oscillator, propagating in a free space,is preferably linearly polarized in a second spatial direction.
 37. Atransceiver as set forth in claim 36, characterized in that the firstspatial direction coincides with the second spatial direction.
 38. Atransceiver as set forth in claim 36, characterized in that the firstspatial direction is orthogonal to the second spatial direction.
 39. Atransceiver as set forth in claim 36, characterized in that the receiveris provided with a polarization means, separating a radiation, linearlypolarized in the first spatial direction, from a radiation, impinging onit.
 40. A transceiver as set forth in claim 36, characterized in thatthe receiver is provided with polarization means, separating aradiation, linearly polarized in the second spatial direction, from aradiation, impinging on it.
 41. A transceiver as set forth in claim 26,characterized in that the frequencies of the first and secondoscillators of the composite radiation are simultaneously increased ordecrease in a sufficiently wide range of frequencies, but saidservocontrolling unit saves said servocontrolling of frequency of thesecond oscillator frequency of the first oscillator radiation in all thementioned range of the frequencies.
 42. A transceiver of system forimaging of MMW/SMMW images for an obtainment of detail information abouta radiation, dispersed by the object, under conditions of low level ofthe object illumination power, comprising a receiver for directamplification and detection of MMW/SMMW radiation, intended for areceiving of MMW/SMMW radiation images in said system for imaging in aplane of its focusing element focused image, a source of MMW/SMMWradiation, intended for an illumination of the object, which dispersesthe source radiation into the direction of the object, the receiver fordirect amplification and detection includes a receiving antenna,connected to an MMW/SMMW amplifier, a signal of which is fed to asquare-law detector, a high-frequency or low-frequency analyzer ofsignal, an input of which is connected via a filter to an output of saidsquare-law detector, means for processing and displaying, connected toan output of the signal analyzer, the radiation source consists of acomposite radiation source and diffuser, which is illuminated by aradiation of said composite radiation source and which disperses to aside of the object a radiation, impinging on the diffuser, said diffuserconsists of spatially distributed point scatterers which are designedwith functions to realizing a distinctive modulation of radiation,dispersed by them, a source of composite radiation, consisting of afirst radiation oscillator, connected to a first directional coupler anddividing the signal of the first oscillator with respect to a power ontoa greater and smaller portions, and of a second radiation oscillator,connected to a second directional coupler, dividing the signal of thesecond oscillator with respect to a power onto a greater and smallerportions, output antenna system, intended for a transmission of saidgreater portions of power of signals of the first and second oscillatorsin a free space preferably by the same way, a servocontrolling unit, toinputs of which from the correspondent outputs of said directionalcouplers there are fed said signals of smaller power of correspondentlyfirst and second oscillators and a servocontrolling unit which isintended for servocontrolling of radiation frequency of the secondradiation oscillator by frequency of the first radiation oscillator, andan oscillator of reference signal, intended for an activating of theservocontrolling unit and for a generating of the reference signal forsaid signal analyzer.
 43. A transceiver as set forth in claim 42,characterized in that said signal analyzer represents by itself a bandfilter with a central pass frequency, corresponding to a correspondentfrequency of said reference signal oscillator, connected to ananalog-digital converter, realizing digital samplings of signal andfillings by these samplings a memory of the processing means, realizinga processing of these samplings in order to obtain a spectralcomposition of this signal.
 44. A transceiver as set forth in claim 43,characterized in that said analyzer is additionally consists of mixer, asignal input of which is connected to an output of said band filter, butto a reference input of said mixer there is fed a signal of thereference signal oscillator, and an output signal of said mixer via thefilter is fed to an input of the analog-digital converter, realizingdigital samplings of signal and fillings by these samplings the memoryof the processor, besides the processing means realizes a digitalprocessing of these samplings in order to obtain a spectral compositionof this signal.
 45. A transceiver as set forth in claim 42,characterized in that the servocontrolling unit represents by itself amixer, inputs of which are intended for a receiving of the smallersignal portions of said first and second oscillators and are connectedto the correspondent outputs of said first and second directionalcouplers, and which realizes a separation of the difference frequencysignal out of said signals for feeding of this difference frequencysignal via the band filter to one input of the phase detector, anotherinput of which is intended for a receiving of signal of said referencesignal oscillator, but an error signal of the phase detector, which is asignal of phase mismatch between the difference frequency signal of thesignals of said first and second oscillators and the signal of thereference frequency oscillator, is fed to a controlling electrode of thesecond oscillator for varying the frequency of the second oscillatorsignal for decreasing said phase mismatch.
 46. A transceiver as setforth in claim 42, characterized in that the receiver for the directamplification and detection is mounted on a scanning device with acapability to receive of complete image radiation, formed by a system ofimaging by means of the heterodyne receiver scanning in a plane offocused image of this system.
 47. A transceiver as set forth in claim42, characterized in that in the area of the of focused image of thefocusing element there is positioned an array of said receivers for thedirect amplification and detection in such a manner that antennae ofsaid receivers are disposed in a zone of the plane of focused image ofthe focusing element.
 48. A transceiver as set forth in claim 43,characterized in that there is used a set of said sources of compositeradiation, besides the frequencies of signals of the referenceoscillators of the correspondent sources differ from each other, but toan output of the square-law detector of the receiver for the directamplification and detection there are parallel connected several saidanalyzers of signals, a number of which equals to a number of saidsources of composite radiation in said set, and a central frequency ofthe band filter of the correspondent analyzer equals to a frequency ofsignal of the reference oscillator of the correspondent source of thecomposite radiation.
 49. A transceiver as set forth in claim 43,characterized in that there is used a set of said sources of compositeradiation, besides the frequencies of signals of the referenceoscillators of the correspondent sources differ from each other, but toan output of the square-law detector of the receiver for the directamplification and detection there are parallel connected several saidanalyzers of signals, a number of which equals to a number of saidsources of composite radiation in said set, and a central frequency ofthe band filter of the correspondent analyzer equals to a frequency ofsignal of the reference oscillator of the correspondent source of thecomposite radiation, and, besides, to a reference input of mixer of saidsignal analyzer there is fed a signal of reference oscillator of saidsource of the composite radiation.
 50. A transceiver as set forth inclaim 49, characterized in that the various sources of compositeradiation of the set of the sources illuminate preferablyspatially-distinctive portions of the diffuser or object.
 51. Atransceiver as set forth in claim 50, characterized in that the varioussources of composite radiation of the set of the sources haveessentially different their average frequencies, calculated as anarithmetic mean of the frequencies of correspondent paired oscillators.52. A transceiver as set forth in claim 42, characterized in that aradiation of said greater portion of signal of the first oscillator,propagating in a free space, is preferably linearly polarized in a firstspatial direction, but a radiation of said greater portion of signal ofthe second oscillator, propagating in a free space, is preferablylinearly polarized in a second spatial direction.
 53. A transceiver asset forth in claim 52, characterized in that the first spatial directioncoincides with the second spatial direction.
 54. A transceiver as setforth in claim 52, characterized in that the first spatial direction isorthogonal one with respect to the second spatial direction.
 55. Atransceiver as set forth in claim 52, characterized in that the receiveris provided with a polarization means, separating a radiation, linearlypolarized in the first spatial direction, from a radiation, impinging onit.
 56. A transceiver as set forth in claim 52, characterized in thatthe receiver is provided with polarization means, separating aradiation, linearly polarized in the second spatial direction, from aradiation, impinging on it.
 57. A transceiver as set forth in claim 42,characterized in that the frequencies of the first and secondoscillators of the composite radiation are simultaneously increased ordecreased in a sufficiently wide range of frequencies, but saidservocontrolling unit saves said servocontrolling of frequency and phaseof the second oscillator by frequency and phase of the first oscillatorin all the mentioned range of the frequencies.
 58. A transceiver as setforth in claim 42, characterized in that said distinctive modulation ofradiation, dispersing by means of point dispersers of the diffuser, is aphase modulation.
 59. A transceiver as set forth in claim 42,characterized in that said distinctive modulation of radiation,dispersing by means of point dispersers of the diffuser, is an amplitudemodulation.
 60. A diffuser illuminator for imaging system in MMW/SMMWrange, intended for an illumination of inspection area by means ofencoded spatially-non-coherent radiation, illuminated by means of atleast one radiation source in MMW/SMMW range, designed in the form oflimited amount of the same sets of separate independent elements ofradiation, all the physical parameters of radiation or their portion ofeach from said radiation elements inside of each set are(is)) differentwith respect to physical parameters of radiation of other elements ofradiation, wherein said diffuser is positioned at a distance from saidradiation source and intended to be illuminated by said source radiationand further to scatter the incident radiation toward said inspectionarea, the diffuser is designed with a capability of a realization offunction of decreasing of spatial coherence of the radiation, scatteredby it, each separate independent element of radiation of the radiationsource of any said set is designed with a capability of encoding theemitted radiation, including also its modulation of any kind, differentfrom encoding of the radiation of other separate independent elementfrom the same set or from anyone other set, besides, the independentsources from one said set illuminate preferably the same spatial portionof said diffuser, but the independent sources of various sets illuminatepreferably spatially different portions of said diffuser.
 61. A diffuserilluminator as set forth in claim 60, characterized in that the diffuseris designed in the form of spatially-distributed set of point dispersingelements, dispersing an impinging radiation by distinctive way withrespect to one another owing to a distinctive modulation of theirdispersing properties along an arbitrary shape of underlying surface.62. A diffuser illuminator as set forth in claim 61, characterized inthat said underlying surface has the given shape, but the sets of theindependent elements of radiation, illuminating the diffuser, arepositioned with respect to the diffuser with a capability of provisionof the most range of impinging angles of the radiation, dispersed by thediffuser into the inspection area.
 63. A diffuser illuminator as setforth in claim 61, characterized in that the dispersing element isdesigned in the form of mirror reflecting element, mounted on apiece-flat base, besides, distinctly reflecting elements are designedwith a capability of movement with respect to the correspondent base bydistinctive from each other way and at a distance, that does not exceeda half of length of backlighting radiation.
 64. A diffuser illuminatoras set forth in claim 63, characterized in that the for a realization ofmovement of the elements they are fastened to magnetic cores of currentinductance coils or to piezo-elements, fed by means of electricalcurrents, which are accidental or regularly changeable in time bydistinctive way.
 65. A diffuser illuminator as set forth in claim 61,characterized in that the dispersing element is designed in the form ofmesomorphic cell, besides, optical properties of various independentmesomorphic cells of such a diffuser are variable by accidental orregularly distinctive way for different cells.
 66. A diffuserilluminator as set forth in claim 60, characterized in that the diffuseris designed in the form of rotating reflector with an accidental surfaceof reflection.
 67. A diffuser illuminator as set forth in claim 60,characterized in that the diffuser is designed in the form of a set ofcorrespondently small reflectors with an accidental surface ofreflection, each of which rotates around own rotation axis and each ofwhich is illuminated by own said set of the independent radiationelements, which are positioned together with said sets in a space insuch a manner, that the most range of impinging angles of the radiation,dispersed by the diffuser into the inspection area, is provided.
 68. Adiffuser illuminator as set forth in claim 60, characterized in that thediffuser is designed in the form of phase antenna array, each elementphase shifter of which is designed with a function of a variation ofphase of passing or reflected radiation, which is distinctive in time.69. A diffuser illuminator as set forth in claim 61, characterized inthat said independent elements are designed with a capability ofgeneration of radiation, which is linearly polarized in a first spatialdirection, but said dispersing element is designed in the form ofindependent quasi-optical radiation switch, representing by itself a setof spatially-distributed independent conducting elements, positioned ona flat base, besides, adjacent conducting elements are connected bymeans of non-linear elements, preferably, in the first spatialdirection, besides, a modulation of impedance of the non-linear elementresults in a modulation of amplitude or phase of wave front, impingingnormally onto such a switch depending on resistive or capacitivecharacter of the impedance of said non-linear element.
 70. A diffuserilluminator as set forth in claim 61, wherein the dispersing element isdesigned in the form of antenna, loaded by the impedance.
 71. A diffuserilluminator as set forth in claim 70, characterized in that eachantenna, loaded by the impedance, represents by itself at least twoconducting antenna portions, connected between each other by means ofnon-linear element for a provision with impedance load and equipped eachby correspondent contacts for feeding to said impedance load a voltageof shifting and/or modulation signal for controlling of impedance valueof this load.
 72. A diffuser illuminator as set forth in claim 71,characterized in that as a non-linear element of the impedance loadthere is selected a photo-conducting element, but an optical signal isused as a modulation signal.
 73. A diffuser illuminator as set forth inclaim 71, characterized in that as a non-linear element of the impedanceload there is selected a non-linear semiconductor device from a group,including at least a diode with a Schottky's barrier, or pin-diode, or atransistor, or a bolometer.
 74. A diffuser illuminator as set forth inclaim 71, characterized in that as a non-linear element of the impedanceload there is selected a micro-mechanical switch.
 75. A diffuserilluminator as set forth in claim 60, characterized in that each saidset consists of one independent radiation element.
 76. A diffuserilluminator for imaging systems in MMW/SMMW range, intended for anillumination of inspection area by means of encodedspatially-non-coherent radiation, comprising at least one radiationsource in MMW/SMMW range, and a diffuser, positioned at a distance fromsaid radiation source and intended for its illumination by means of saidsource radiation and to further scatter the incident radiation towardsthe inspection area, the diffuser is designed in the form of a set ofspatially-distributed radiation point scatterers, which are designed insuch a manner, that they realize an amplitude modulation of radiation,scattered by them distinctly with respect to one another.
 77. A diffuserilluminator as set forth in claim 76, characterized in that thedispersing element of the diffuser is designed in the form ofindependent quasi-optical radiation switch, designed in the form of aset of spatially-distributed conducting elements, the adjacentconducting elements inside of said set are connected to each otherpreferably in a first spatial direction by means of connecting elements,each of which has a first impedance state, being a high-conducting one,and a second impedance state, being a low-conducting one, the conductingelements of each of spatially-distributed set, as a response on aradiation, impinging on the given set, being preferably polarized in thefirst spatial direction, have a characteristic impedance, which becomesinsufficient in a combination with the first impedance states of theconnecting elements, positioned preferably in the first state so, that aradiation, impinging onto the given spatially-distributed set, beingpreferably polarized in the first spatial direction, occurs preferablyreflected by said spatially-distributed set, the conducting elementseach of said set, connected by means of connecting elements, beingpreferably in the second impedance state, have a characteristicimpedance, as a response on said impinging radiation in combination withthe second impedance states of said connecting elements on the givenset, high one, and such a quasi-optical switch occurs transparent onefor a radiation, impinging on it.
 78. A diffuser illuminator as setforth in claim 77, characterized in that as a non-linear element of theimpedance load there is selected a photo-conducting element, but anoptical signal is used as a modulation signal.
 79. A diffuserilluminator as set forth in claim 77, characterized in that as anon-linear element of the impedance load there is selected a non-linearsemiconductor device from a group, including at least a diode with aSchottky's barrier, or pin-diode, or a transistor, or a bolometer.
 80. Adiffuser illuminator as set forth in claim 77, characterized in that asa non-linear element of the impedance load there is selected amicro-mechanical switch.
 81. A diffuser illuminator as set forth inclaim 77, characterized in that an independent spatial structure isdesigned in the form of two conducting portions of antenna of MMW and/orsub-millimeter range.
 82. A diffuser illuminator as set forth in claim77, characterized in that a radiation source is designed so that itcomprises additionally polarization means, passing the radiation in sideof the diffuser, which is polarized only in the first spatial direction.83. A diffuser illuminator as set forth in claim 76, characterized inthat it is designed in the form of a set of separate independentradiation elements, all the physical parameters of radiation or theirportion of each from said radiation elements inside of each set are (is)different with respect to physical parameters of radiation of otherelements of radiation, each separate independent element of radiation ofthe radiation source of any said set is designed with a capability ofown radiation encoding, including also its modulation, different fromencoding of radiation of other separate independent elements ofradiation.
 84. A diffuser illuminator as set forth in claim 76,characterized in that characteristic angular dimensions of said pointdispersers of the diffuser, observed from said inspection area, are lessthan angular dimensions of own diffuser, observed from the same spatialpoint of the inspection area.
 85. A diffuser illuminator as set forth inclaim 76, characterized in that said point dispersers are preferablyspatially-continuously and preferably spatially-regularly distributed.86. A method for millimeter and sub-millimeter wave imaging, consistingin the steps of forming a composite radiation in the millimeter andsub-millimeter range of waves, consisting of partial radiations,differing from one another by values of physical features, directing ofthe formed composite radiation towards to observed object, receiving theradiation, primarily scattered with the observed object, through afocusing means, transforming of the received composite radiation toelectrical signals and generating a visually accepted image of theobserved object in accordance with the given electrical signals,characterized in that each partial radiation is additionally encoded bymeans of its modulation, which differs from a modulation of otherpartial radiations, the partial radiations are directed to a diffuserfor decreasing their spatial coherence and/or their scattering byspatially-different radiation-modulating portions of the diffuser inorder to originate radiation components each of which is secondarydistinctly modulated and exhibits a particular direction of incidence onobserved object, after reflecting said components from, i.e. scatteringwith, the observed object focusing of the components on the receivingmeans which is designed with capability to independently receiveportions of a radiation each of which is incident from a particularspatial portion of inspection area with the observed object, receivingby means of said receiving means the reflected multi-component radiationindependently from each spatial portion of inspection area with theobserved object and transforming by means of said receiving means thereceived said portions multi-components radiation in correspondentmatrix set of electrical signals, decoding and generating secondaryelectrical signals from said matrix set electrical signals, arrangingsaid secondary signals into secondary matrix sets of the secondaryelectrical signals such that the secondary electrical signals from thesame said set correspond to distinctly received said portions of aparticular distinctly encoded radiation component which arecorrespondingly associated with said complementary spatial portions ofinspection area with the observed object, generating matrix partialimages of inspection area with the observed object from correspondentsecondary matrix sets of secondary electrical signals, forming aresultant image of inspection area with the observed object by combiningsaid partial matrix partial images or their portions.
 87. A method formillimeter and sub-millimeter wave imaging, consisting in the steps offorming a composite radiation in the millimeter and sub-millimeter rangeof waves, consisting of partial radiation components, differing from oneanother by values of physical features, directing of the formedcomposite radiation towards to observed object, receiving the radiation,primarily scattered with the observed object, through a focusing means,transforming of the received composite radiation to electrical signalsand generating a visually accepted image of the observed object fromsaid electrical signals, characterized in that each partial radiationcomponent is additionally encoded by means of its modulation, whichdiffers from a modulation of other partial radiation components, afterreflecting said radiation components from, i.e. scattering with, theobserved object focusing of the components on the receiving means whichis designed with capability independently to receive portions of aradiation each of which is incident from a particular spatial portion ofthe inspection area with the observed object, distinctly receiving bymeans of said receiving means portions of the reflected, i.e. scattered,multi-component radiation independently from each spatial portion of theinspection area with the observed object and transforming by means ofsaid receiving means the received said portions multi-componentsradiation in correspondent matrix set of electrical signals, decodingand generating secondary electrical signals from said matrix setelectrical signals such that arranging said secondary signals intosecondary matrix sets of secondary electrical signals such thatsecondary electrical signals from the same said set correspond todistinctly received said portions of a particular distinctly encodedradiation component which are correspondingly associated with saidcomplementary spatial portions of the inspection area with the observedobject, generating matrix partial images of the inspection area with theobserved object from correspondent secondary matrix sets of secondaryelectrical signals, forming a resultant image of the inspection areawith the observed object by combining said partial matrix partial imagesor their portions.